Efficient and color-tunable visible-light emission is achieved in fluorescent dye-doped oligo(phenylenevinylene)-silica mesostructured films through fluorescence resonance energy transfer from a blue-light-emitting organosilica to a yellow-light-emitting dye (see figure). Tuning of the composition realizes pseudo white-light emission with a quantum yield of 67%. Utilization of both walls and pores of the mesostructured organosilicas is effective to construct highly functional systems.