The photoproduced cation radical of N-methylphenothiazine (PC1) doped into phenyltriethoxysilane (PhiTEOS), vinyltriethoxysilane (VTEOS), and methyltriethoxysilane (METOS) was studied with electron spin resonance (ESR) and electron nuclear double resonance (ENDOR). The photoinduced charge separation efficiency was determined by integration of ESR spectra which correspond to the amount of photoproduced cation radical in the matrixes. This was correlatively studied with the polarity and pore size of the gel matrixes. The relative polarity of the matrixes was determined by measuring lambda(max) values of PC1 in the different matrixes. The relative pore size among the matrixes was determined by measuring relative proton matrix ENDOR line widths of the photoproduced cation radical of PC1. The decay kinetic constants of the cation radical of PC1 in the different matrixes were relatively studied with fitting the biexponential decay curves after exposure at the ambient condition. This is correlatively interpreted with the polarity and pore size of the matrixes.