As filed with the Securities and Exchange Commission on July 3, 2024 Registration No. 333-279550 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 AMENDMENT NO. 1 TO FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 CLEARSIGN TECHNOLOGIES CORPORATION Copies to: Blake Baron, Esq. Nimish Patel, Esq. Mitchell Silberberg & Knupp LLP 437 Madison Avenue New York, New York 10022 Phone: (212) 509-3900 (Exact name of registrant as specified in its charter) | Delaware | | --- | | ...

As filed with the Securities and Exchange Commission on May 20, 2024 Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 CLEARSIGN TECHNOLOGIES CORPORATION (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation or organization) (Primary Standard Industrial Delaware 3823 26-2056298 (I.R.S. Employer Identification No.) 8023 East 63 Place, Suite 101 Tulsa, Okl ...