Thiol-ene radical addition by photolysis is a highly efficient click reaction of sufhydryl groups with reactive enes that has been extensively explored as a promising means to construct multifunctional materials. Here, photo-induced thiol-ene crosslinked films composed of linear methacrylate copolymer polythiols (MCPsh) are reported. Well-defined MCPsh copolymers were prepared by thiol-responsive cleavage of pendant disulfide linkages positioned in the corresponding methacrylate copolymers with narrow molecular weight distribution which were synthesized by a controlled radical polymerization method. With a commercially available multifunctional acrylate as a model ene, photo-induced thiol-ene radical polyaddition of these polythiols is competitive to free-radical homopolymerization of acrylates, yielding crosslinked films exhibiting rapid cure, uniform network, and enhanced mechanical properties; these properties are required for high performance coating materials. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2860-2868.