A household halogen lamp is used to promote the ring-opening photopolymerization of epoxides in the presence of coumarin moiety containing Pt(II) complex/silane/iodonium salt combinations (epoxide/acrylate interpenetrated polymer networks can also be synthesized). Excellent polymerization profiles are obtained (conversions >70%) under this selected very soft irradiation. These Pt(II) complexes behave as photocatalysts in an oxidative cycle. A photoluminescent polymer can be in situ synthesized thanks to the luminescence properties of these complexes. The mechanisms are investigated by ESR, laser flash photolysis, and luminescence experiments.