Various PS-based graft copolymers including polystyrene-graft-poly(methyl methacrylate) and poly(styrene-graft-poly(ethylene glycol) methacrylate) are prepared via subsequent visible light radical photopolymerization and iniferter processes. Thus, poly(styrene-co-4-chloromethylstyrene) P(S-co-VBC) is synthesized by light induced free-radical polymerization. Then, chloride moieties are substituted with triphenylmethyl (trityl) groups to give trityl-substituted PS (PS-trityl) under visible light irradiation using dimanganese decacarbonyl (Mn-2(CO)(10)) photochemistry. Side chains are then grafted from PS-trityl backbone via iniferter process to give desired graft copolymers in a controlled manner. The precursor intermediates and the final graft copolymers are analyzed by H-1 NMR, FT-IR, and GPC measurements. (c) 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1344-1348