As filed with the Securities and Exchange Commission on September 25, 2025 (Primary Standard Industrial Classification Code Number) (I.R.S. Employer Identification Number) Registration No. 333-[●] UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 Professional Diversity Network, Inc. (Exact name of registrant as specified in its charter) Delaware 7370 80-0900177 (State or other jurisdiction of incorporation or organization ...