Semiconductor materials have received substantial attention as photocatalysts for controlling water pollution. Among these materials, perovskite-structured SrSnO 3 is a promising candidate for this application, whereas BaSnO 3 exhibits very low activity. In the present work, Sr 1-x Ba x SnO 3 (x = 0, 0.25, 0.50, 0.75 and 1) was synthesized by solid-state reaction and was applied in the photocatalytic discoloration of the organic dye Remazol Golden Yellow. The perovskite structure was obtained for all compositions of the solid solutions with both Sr The two materials appear to feature different mechanisms of photodegradation: the direct mechanism prevails in the case of BaSnO 3 , whereas the indirect mechanism appears to play a key role in the case of SrSnO 3 .