Professional Diversity Network, Inc.

As filed with the Securities and Exchange Commission on June 25, 2026.

Registration No. 333-[●]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM S-1

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

(Exact name of registrant as specified in its charter)

55 E. Monroe Street, Suite 2120

Chicago, Illinois 60603

(312)614-0950

(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Xun Wu

Chief Executive Officer

55 E. Monroe Street, Suite 2120

Chicago, Illinois 60603

(312) 614-0950

(Name, address, including zip code, and telephone number, including area code, of agent for service)

Copies to:

Approximate date of commencement of proposed sale to the public: As soon as practicable after the effective date of this Registration Statement.

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box. ☒

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

If this Form is a post-effective amendment filed pursuant to Rule 462(d) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering. ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act. ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 7(a)(2)(B) of the Securities Act. ☐

The Registrant hereby amends this Registration Statement on such date or dates as may be necessary to delay its effective date until the Registrant shall file a further amendment which specifically states that this Registration Statement shall thereafter become effective in accordance with Section 8(a) of the Securities Act of 1933, as amended, or until the Registration Statement shall become effective on such date as the Commission, acting pursuant to said Section 8(a), may determine.

The information in this prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any state where the offer or sale is not permitted.

UP TO 15,713,387 UNITS

EACH UNIT CONSISTING OF

ONE SHARE OF COMMON STOCK AND

UP TO 15,713,387 PRE-FUNDED UNITS

EACH PRE-FUNDED UNIT CONSISTING OF

ONE PRE-FUNDED WARRANT TO PURCHASE ONE SHARE OF COMMON STOCK AND

UP TO 31,426,774 SHARES OF COMMON STOCK UNDERLYING THE WARRANTS AND THE PRE-FUNDED WARRANTS

We are offering on a best-efforts basis up to 15,713,387** ** units (the “Units”), each consisting of one share of common stock, par value $0.01 per share (“Common Stock”), of Professional Diversity Network, Inc. (“PDN,” the “Company,” “we,” “our,” or “us”), together with one warrant (each, a “Warrant”), each to purchase one share of Common Stock, at an assumed public offering price of $0.6364 per Unit, which was the last reported sale price of our Common Stock on the Nasdaq Capital Market on June 18, 2026. The Units will not be certificated or issued as stand-alone securities.

We are also offering pre-funded units (the “Pre-Funded Units”), with each Pre-Funded Unit consisting of (i) one pre-funded warrant (each, a “Pre-Funded Warrant”) to purchase one share of Common Stock and (ii) one Warrant, to those purchasers whose purchase of Units in this offering would otherwise result in the purchaser, together with its affiliates and certain related parties, beneficially owning more than 4.99% (or, at the election of the purchaser, 9.99%) of our outstanding shares of Common Stock immediately following the consummation of this offering. The purchase price of each Pre-Funded Unit will equal the public offering price per Unit minus $0.01, and the exercise price of each Pre-Funded Warrant will equal $0.01 per share. The Pre-Funded Warrants will be immediately exercisable (subject to the beneficial ownership cap) and may be exercised at any time until exercised in full. For each Pre-Funded Unit sold, the number of Units we are offering will be decreased on a one-for-one basis. The Pre-Funded Units have no stand-alone rights and will not be certificated or issued as stand-alone securities.

Each Warrant will be exercisable immediately upon issuance at an initial exercise price of $0.6364 per share (representing 100% of the assumed public offering price of $0.6364 per Unit, the last reported sale price of our Common Stock as reported on the Nasdaq Capital Market on June 18, 2026) and will expire on the third anniversary of the date of issuance. A holder of Warrants or Pre-Funded Warrants may not exercise any portion of such warrants if, after giving effect to such exercise, the holder, together with its affiliates and any other person or entity acting as a group, would beneficially own more than 4.99% (or, at the election of the holder, up to 9.99%) of our outstanding Common Stock immediately after exercise, subject to the terms and conditions of such warrants.

The shares of Common Stock and Pre-Funded Warrants, as the case may be, can each be purchased in this offering only with the accompanying Warrants that are part of a Unit or Pre-Funded Unit, but the Units and the Pre-Funded Units have no stand-alone rights and will not be certificated, and the components of the Units or the Pre-Funded Units will be immediately separable and will be issued separately in this offering.

We are also registering the shares of Common Stock issuable from time to time upon exercise of the Pre-Funded Warrants and Warrants included in the Units and Pre-Funded Units offered hereby.

Our Common Stock is listed on the Nasdaq Capital Market under the symbol “IPDN.” On June 24, 2026, the last reported sale price of our Common Stock on the Nasdaq Capital Market was $0.619 per share.

There is no established public trading market for the United, Pre-Funded Units, Warrants or the Pre-Funded Warrants, and we do not expect such a market to develop. We do not intend to apply for listing of the Warrants or the Pre-Funded Warrants on any securities exchange or nationally recognized trading system. Without an active trading market, the liquidity of the Warrants will be limited.

The public offering price of the Units in this offering will be determined at the time of pricing and may be at a discount to the then-current market price of our Common Stock. The actual public offering price per Pre-Funded Unit will equal the public offering price per Unit minus $0.01. The final public offering price will be determined through negotiations among us, the Placement Agent (defined below) and the investors, based upon a number of factors, including our history and our prospects, the industry in which we operate, our past and present operating results, the previous experience of our executive officers and the general condition of the securities markets at the time of this offering.

The securities will be offered at a fixed price and are expected to be issued in a single closing. Investors purchasing securities offered hereby will have the option to execute a securities purchase agreement with us. Investors who do not enter into a securities purchase agreement shall rely solely on this prospectus in connection with the purchase of our securities in this offering. We expect this offering to be completed not later than two (2) trading days following the commencement of sales in this offering and we will deliver all securities to be issued in connection with this offering delivery versus payment/receipt versus payment upon receipt of investor funds received by us. Accordingly, neither we nor the Placement Agent have made any arrangements to place investor funds in an escrow account or trust account since the Placement Agent will not receive investor funds in connection with the sale of the securities offered hereunder.

We have engaged Maxim Group LLC (“Maxim” or the “Placement Agent”) to act as our exclusive placement agent in connection with this offering. The Placement Agent has no obligation to purchase and is not purchasing or selling the securities offered pursuant to this prospectus and is not required to arrange for the purchase or sale of any specific number or dollar amount of our securities, but will use its reasonable best efforts to arrange for the sale of the securities offered hereby. Because there is no minimum offering amount required as a condition to closing of this offering, the actual offering amount, the Placement Agent’s compensation and proceeds to us, if any, are not presently determinable and may be substantially less than the maximum offering amount set forth in this prospectus. We have agreed to pay the Placement Agent the compensation set forth under “Plan of Distribution” and to reimburse certain expenses of the Placement Agent. See “Plan of Distribution” for additional information regarding these arrangements.

Investing in our securities involves a high degree of risk. See“Risk Factors”** beginning on page** 4** of this prospectus, as well as other information included in this prospectus, to read about factors you should consider before investing in our securities.**

We will deliver the shares of Common Stock being issued to the purchasers electronically and will electronically deliver to such investors electronic warrant certificates for each of the Pre-Funded Warrants and the Warrants sold in this offering, upon closing and receipt of investor funds for the purchase of the securities offered pursuant to this prospectus. If we complete this offering, net proceeds will be delivered to us on the closing date. We expect to deliver the securities against payment in U.S. dollars in New York, NY to investors on or about [●], 2026, subject to satisfaction of certain customary closing conditions.

Neither the United States Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Maxim Group LLC

Prospectus dated [●], 2026.