A composite of CdS and ZnS was prepared by simple solid state mechanochemical method and it was used for photocatalytic degradation of Evan’s blue. The photocatalytic efficiency of CdS-ZnS composite was compared with pure CdS and ZnS. The effect of various parameters such as pH, the concentration of dye, amount of semiconductor and light intensity was observed. The optimum conditions obtained for this degradation were: Evan’s blue = 1.3 × 10‾5 M, pH = 5.5, amount of composite = 0.12 g and light intensity = 50.0 mWcm‾2. It was found that coupled chalcogenide CdS - ZnS shows better photocatalytic activity as compared with pure CdS and ZnS for the degradation of Evan’s blue in the presence of visible light.