A new visible light-induced controlled radical polymerization of methacrylate with perfluoro-1-iodohexane (CF3(CF2)(5)I) as the initiator in the presence of a photoredox catalyst (fac-[Ir(ppy)(3)]) was developed. Mechanistically, a photoexcited fac-[Ir(ppy)(3)]* complex reacted with dormant C-I species to generate the chain propagating radical and (IrI)-I-IV complex, which could be reversibly reduced by the propagating radical. The molecular weight (M-n) and the corresponding distribution index (M-w/M-n=1.4) were controlled in the polymerization of methyl methacrylate (MMA). For the polymerization of functional monomers, such as glycidyl methacrylate (GMA) and trifluoroethyl methacrylate, their monomer conversions could be up to 96 and 94%, respectively. No polymerization reaction took place without external light stimulation, indicating that the system was an ideal photo on-off switchable system. Furthermore, a clean diblock copolymer PMMA-b-PGMA was successfully synthesized with PMMA-I as the macroinitiator. With CF3(CF2)(5)I as the initiator, short CF3(CF2)(5)- group tags were introduced on the produced polymer chains. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3283-3291