Citraconimide is a 3-methylmaleimide derivative. Citraconimide has thiol affinity and can undergo highly regioselective addition with a variety of alkyl thiols. Citraconimide derivatives show growth inhibitory activity against HeLa cells. Citraconimide can be modified by N-substitution, halogenation and other reactions for use in bioactive molecule design and drug development research[1].