Moleculin Biotech, Inc.

Moleculin Biotech, Inc.

PROXY STATEMENT

GENERAL INFORMATION

For the Special Meeting of Stockholders

To Be Held on April 15, 2026

Our Board of Directors is soliciting proxies to be voted at the Special Meeting of Stockholders (the“Special Meeting”) to be held at the corporate offices at 5300 Memorial Drive, Suite 950, Houston, TX 77007, on April 15, 2026 at 10:00 a.m., local time, for the purposes set forth in the attached Notice of Special Meeting of Stockholders (the“Notice”) and in this Proxy Statement. This Proxy Statement and the proxies solicited hereby are being first sent or delivered to stockholders of the Company on or about March 9, 2026.

As used in this Proxy Statement, the terms“Company,”* “we,” “us,” “our” and*“Moleculin”* refer to Moleculin Biotech, Inc., and the terms*“Board of Directors”* and*“Board”* refers to the Board of Directors of the Company.*

Questions and Answers about these Proxy Materials and the Special Meeting

What information is contained in this Proxy Statement?

This information relates to the proposals to be voted on at the Special Meeting, the voting process, and certain other required information.

Can I access the Company’s proxy materials electronically?

Yes. The Proxy Statement and form of Proxy are available at https://materials.proxyvote.com/60855D. To view this material, you must have available the control number located on the proxy card or, if shares are held in the name of a broker, bank or other nominee, the voting instruction form.

What does it mean if I receive more than one set of proxy materials?

It means your shares are registered differently or are in more than one account. Please provide voting instructions for each account for which you have received a set of proxy materials.

Who is soliciting my vote pursuant to this Proxy Statement?

Our Board is soliciting your vote at the Special Meeting. We have engaged Okapi Partners LLC (“Okapi"), a proxy solicitation firm, at an approximate cost of $12,500, to solicit proxies on behalf of the Company. Okapi may solicit the return of proxies, either by mail, telephone, email or through personal contact. The cost of solicitation will be borne by us, including the fees of Okapi as well as the reimbursement of their expenses. Our directors and employees may also solicit proxies in person, by telephone, fax, electronic transmission or other means of communication. We will not pay these directors and employees any additional compensation for these services. We will ask banks, brokerage firms, and other institutions, nominees, and fiduciaries to forward these proxy materials to their principal, and to obtain authority to execute proxies, and will reimburse them for their expenses.

Who is entitled to vote?

Only stockholders of record at the close of business on February 20, 2026 (the "Record Date") will be entitled to vote at the Special Meeting.

How many shares are eligible to be voted?

As of the Record Date, we had 4,933,110 shares of common stock outstanding. Each outstanding share of our common stock will entitle its holder to one vote on each of the matters to be voted on at the Special Meeting.

What am I voting on?

You are voting on the following matters:

1.Nasdaq Proposal. For purposes of complying with Nasdaq Listing Rule 5635(d), to approve the issuance of up to 6,367,956 shares of Company common stock upon the exercise of certain warrants issued on February 20, 2026 in a private placement (the “Nasdaq Proposal”).

2.Name Change Proposal. To approve an amendment to the Company’s Amended and Restated Certificate of Incorporation, as amended, to change the Company’s name from Moleculin Biotech, Inc. to Moleculin Inc. (the “Name Change Proposal”).

3.Adjournment Proposal. To approve an adjournment of the Special Meeting, if necessary, to solicit additional proxies if there are not sufficient votes in favor of the Nasdaq Proposal or the Name Change Proposal (the “Adjournment Proposal”).

How does the Board recommend that I vote?

The Board unanimously recommends that you vote your shares as follows:

None of our directors have informed us in writing that he or she intends to oppose any action intended to be taken by us at the Special Meeting.

How many votes are required to hold the Special Meeting and what are the voting procedures?

Quorum Requirement: As of the Record Date, 4,933,110 shares of the Company’s common stock were issued and outstanding. The holders of one-third in voting power of the outstanding shares of common stock entitled to vote at the Special Meeting, present in person or represented by proxy, constitutes a quorum for the purpose of adopting proposals at the Special Meeting. If you submit a properly executed proxy, then you will be considered part of the quorum.

Required Votes: Each outstanding share of our common stock is entitled to one vote on each proposal at the Special Meeting. If there is a quorum at the Special Meeting, the matters to be voted upon by the stockholders require the following votes for such matter to be approved:

If a broker indicates on its proxy that it submits to the Company that it does not have authority to vote certain shares held in “street name,” the shares not voted are referred to as “broker non-votes.” Broker non-votes occur when brokers do not have discretionary voting authority to vote certain shares held in “street name” on particular proposals under the rules of the New York Stock Exchange, and the “beneficial owner” of those shares has not instructed the broker how to vote on those proposals. If you are a beneficial owner and you do not provide instructions to your broker, bank or other nominee, your broker, bank or other nominee is permitted to vote your shares for or against “routine” matters. Brokers are not permitted to exercise discretionary voting authority to vote your shares for or against “non-routine” matters.

How can I vote my shares in person and participate at the Special Meeting?

If you plan to attend the Special Meeting and vote in person on April 15, 2026, or at a later date if the meeting is adjourned or postponed, we will give you a ballot when you arrive. However, if your shares are held in the name of your broker, bank or other nominee, you must bring a power of attorney executed by the broker, bank or other nominee that owns the shares of record for your benefit and authorizing you to vote the shares.

Even if you plan to attend the Special Meeting in person, the Company recommends that you vote your shares in advance, so that your vote will be counted if you later decide not to attend the Special Meeting.

How can I vote my shares without attending the Special Meeting?

If you are the stockholder of record, you may vote by one of the following three methods:

If you elect to vote by mail and you requested and received a printed set of proxy materials, you may mark, sign, date and mail the proxy card you received from us in the return envelope. If you did not receive a printed proxy card and wish to vote by mail, you may do so by requesting a paper copy of the proxy materials (as described below), which will include a proxy card.

Whichever method of voting you use, the proxies identified on the proxy card will vote the shares of which you are the stockholder of record in accordance with your instructions. If you submit a proxy card properly voted and returned through available channels without giving specific voting instructions, the proxies will vote the shares as recommended by our Board.

If you own your shares in “street name,” that is, through a brokerage account or in another nominee form, you must provide instructions to the broker or nominee as to how your shares should be voted. Your broker or nominee will usually provide you with the appropriate instruction forms at the time you receive the proxy materials. If you own your shares in this manner, you cannot vote in person at the Special Meeting unless you receive a proxy to do so from the broker or the nominee.

How may I cast my vote over the Internet or by Telephone?

Voting over the Internet: If you are a stockholder of record, you may use the Internet to transmit your vote up until 11:59 P.M., Eastern Time, on April 14, 2026 (the day before the Special Meeting). Visit https://materials.proxyvote.com/60855D and have your proxy card in hand when you access the website and follow the instructions to obtain your records and to create an electronic voting instruction form.

Voting by Telephone: If you are a stockholder of record, you may call 1-800-690-6903, toll-free in the United States, U.S. territories and Canada, and use any touch-tone telephone to transmit your vote up until 11:59 P.M., Eastern Time, on April 14, 2026 (the day before the Special Meeting). Have your proxy card in hand when you call and then follow the instructions.

If you hold your shares in “street name,” that is through a broker, bank or other nominee, that institution will instruct you as to how your shares may be voted by proxy, including whether telephone or Internet voting options are available.

How may a stockholder bring any other business before the Special Meeting?

The Company’s Fourth Amended and Restated Bylaws (the “Bylaws”) provide that the only matters that may be brought before a special meeting are the matters specified in the notice of meeting, and, as such, stockholders shall not be permitted to propose business at the Special Meeting.

How may I revoke or change my vote?

If you are the record owner of your shares, and you completed and submitted a proxy card, you may revoke your proxy at any time before it is voted at the Special Meeting by:

Please note that attendance at the Special Meeting will not, in itself, constitute revocation of your proxy.

If you own your shares in “street name,” you may later revoke your voting instructions by informing the bank, broker or other holder of record in accordance with that entity’s procedures.

Who is paying for the costs of this proxy solicitation?

The Company will bear the cost of preparing, printing and mailing the materials in connection with this solicitation of proxies. In addition to mailing these materials, officers and regular employees of the Company may, without being additionally compensated, solicit proxies personally and by mail, telephone, facsimile or electronic communication.

We have also engaged Okapi at an approximate cost of $12,500, to solicit proxies on behalf of the Company.

Are there any rights of appraisal?

The Board of Directors is not proposing any action for which the laws of the State of Delaware, our Amended and Restated Certificate of Incorporation or our Bylaws provide a right of a stockholder to obtain appraisal of or payment for such stockholder’s shares.

Who will count the votes?

The inspector of election appointed for the Special Meeting will receive and tabulate the ballots and voting instruction forms. The Board has appointed American Election Services, LLC to serve as the inspector of election.

Where do I find the voting results of the Special Meeting?

The voting results will be disclosed in a Current Report on Form 8-K that we will file with the SEC within four business days after the Special Meeting.

How can I obtain the Company’s corporate governance information?

Our corporate governance information is available on our website at www.moleculin.com under “Investors—Governance.” Our stockholders may also obtain written copies at no cost by writing to us at Moleculin Biotech, Inc., 5300 Memorial Drive, Suite 950, Houston, TX 77007, Attention: Corporate Secretary, or by calling (713) 300-5160.