UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) of THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 Commission File Number 000-14893 RESEARCH FRONTIERS INCORPORATED (Exact name of registrant as specified in its charter) DELAWARE 11-2103466 (State or other jurisdiction of (I.R.S. Employer incorporation or organization) Identification No.) 240 CROSSWAYS PARK DRIVE WOODBURY, NEW YORK 11797-2033 (Addre ...