An efficient strategy for comprehensive utilization of the conjugated sulfonium salt photoacid generator (PAG), namely, 3-{4-[4-(4-N, N'-diphenylamino)-styryl]phenyl} phenyl dimethyl sulfonium hexafluoroantimonate, was developed through photoinitiated cationic photopolymerization (CP) of epoxides and vinyl ether upon exposure to near-UV and visible light-emitting diodes (LEDs; e.g., 365, 385, 405, and 425 nm). Photochemical mechanisms were investigated by UV-vis spectra, molecular orbital calculations, fluorescence, cyclic voltammetry, and electron spin resonance spintrapping analyses. Compared with commercial PAGs, the prepared conjugated sulfonium salt generated H+, which can be used as photoinitiator. Moreover, the fluorescent by products from photodecomposition can be used as photosensitizer of commercial iodonium salt in the photoinitiating systems of CP. These novel D-pi-A type sulfonium-based photoinitiating systems are efficient (epoxide conversion =85-90% and vinyl conversion >90%; LEDs upon exposure to 365-425 nm) even in low-concentration initiators (1%, w/w) and low curing light intensities (10-40 mW cm(-2)). (C) 2016 Wiley Periodicals, Inc.