CitroTech Inc.

Table of Contents

As filed with the Securities and Exchange Commission on September 28, 2026.

Registration No. 333-

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORMS-1

REGISTRATION STATEMENT

UNDER THE SECURITIES ACT OF 1933

CitroTech Inc.

(Exact name of registrant as specified in its charter)

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

Wesley J. Bolsen, Chief Executive Officer

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

With Copies to:

Anthony F. Newton · David E. Danovitch, Esq.

Law Office of Anthony F. Newton · Michael DeDonato, Esq.

8810 Luray Court · Sullivan & Worcester LLP

Rosenberg, Texas 77469 · 1251 Avenue of the Americas, 19th Floor

+1 (832) 452-0269 · New York, NY 10020

(212) 660-3060

APPROXIMATE DATE OF PROPOSED SALE TO PUBLIC:As soon as practicable after this registration statement becomes effective.

If any 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, please 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 Securities and Exchange Commission, acting pursuant to said Section 8(a), may determine.

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

PRELIMINARY PROSPECTUS, SUBJECT TO COMPLETION, DATED SEPTEMBER 28, 2026

1,639,344 Shares of Common Stock

We are offering on a firm commitment basis, up to $7.0 million of our common stock, par value $0.0001 per share (the “Common Stock”).

The assumed public offering price per share of common stock is $4.27. We will use the net proceeds from the offering for working capital and general corporate purposes.

Our Common Stock is listed on the NYSE American LLC (“NYSE American”) under the symbol “CITR.” On September 24, 2026, the per share closing price of our Common Stock was $4.27.

We are a “smaller reporting company” as defined under the federal securities laws and, as such, we have elected to comply with certain reduced reporting requirements for this prospectus and may elect to do so in future filings. See “Risk Factors” and “Prospectus Summary - Implications of Being a Smaller Reporting Company.”

Investing in our Common Stock involves risks. See “Risk Factors” beginning on page 12.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

We have granted a 45-day option to Univest Securities, LLC, as representative of the underwriters (the “Representative”), exercisable one or more times in whole or in part, to purchase up to an additional 245,901 shares of Common Stock. The aggregate number of shares of our Common Stock sold pursuant to the Representative’s option may not exceed 15% of the total shares of our Common Stock sold in this offering.

Delivery of the shares of Common Stock by the underwriters to the purchasers against payment therefor is expected to be made on or about , 2026.

Sole Book-Running Manager

The date of this prospectus is , 2026.