An elegant approach for fast polymer postfunctionalization and step-growth polymerization (via addition reaction) under aerobic condition was developed from visible light photocatalytic thiolene click reaction, employing Ru(bpy)(3)Cl-2 as photoredox catalyst and p-toluidine as redox mediator. The nature of the photoredox catalysts, thiol substrates, and solvents were extensively investigated for this reaction with two types of alkene polymers: polybutadiene and poly(allyl methacrylate)s. The use of N-methyl-2-pyrrolidone as the solvent and p-toluidine as redox mediator remarkably improved the reaction rates and limited the formation of side products. Finally, this highly efficient thiolene reaction was employed for the synthesis of polymers by step-growth addition polymerization.