Two novel series of semiconductor photocatalysts, InMO4 (M= V, Nb, Ta) and RVO4 (R=Y, rare earth), have been developed by crystal and electronic structure control. The new photocatalysts have band gaps narrower than 2.6 eV and showed photocatalytic. activities in evolving hydrogen from water under visible or UV light irradiation. Correlation between the photocatalytic activities and electronic structures of the new photocatalysts were investigated.