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X ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended : December 31 , 2020 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from Title of each class Common stock , par value $ 0.00001 Warrant to purchase common stock , expiring April 20 , 2021 FORM 10 - K to Delaware ( State or other jurisdiction of incorporation or organization ) Commission File Number 333-119366 Large accelerated filer Non - accelerated filer X CELLECTAR BIOSCIENCES , INC . ( Exact name of Registrant as specified in its Charter ) 100 Campus Drive Florham Park , New Jersey 07932 ( Address of principal executive offices , including zip code ) ( 608 ) 441-8120 ( Registrant's telephone number , including area code ) Securities registered pursuant to Section 12 ( b ) of the Act : Trading Symbol ( s ) CLRB CLRBZ ( I.R.S. Employer Identification No. ) Securities Registered pursuant to Section 12 ( g ) of the Act : None 04-3321804 Name of each exchange on which registered Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes No x Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15 ( d ) of the Exchange Act . Yes ¨ No x Indicate by check mark whether the registrant ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) , and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes x No NASDAQ Capital Market NASDAQ Capital Market Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( § 232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes x No 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 . Accelerated filer Smaller reporting company x Emerging growth company 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 13 ( a ) of the Exchange Act .