In recent times, the development of high-performance photocatalysts with broad visible-light adsorption, photo-electrochemical stability and superior charge separation efficiency for clean renewable energy applications has attracted strong interest. A simple sol–gel method was used to prepare CuS-encapsulated ZnCdS nanopellets with varying concentrations ranging from 2 wt.% to 6 wt.%. The formation of ZnCdS@CuS was confirmed by standard experimental and spectroscopic techniques. Under visible-light irradiation, the prepared ZnCdS@CuS (6 wt.%) nanopellets had significantly increased photocatalytic activity towards methylene blue (MB) and rhodamine B (RhB) dye degradation compared with other catalysts. The results showed that the photocatalytic activity of the ZnCdS@CuS (6 wt.%) composite was better than that of pure ZnCdS and CuS. The ZnCdS@CuS (6 wt.%) showed a degradation efficiency of around 99.9% within 150 min for RhB dye and 120 min for MB dye under visible-light irradiation and exhibited high stability when reused. The enhanced degradation performance might be ascribed to the presence of CuS and ZnCdS, which might increase the surface charge transport and separation and extend light absorption to the visible range. We anticipate that our study will point readers towards a new path for developing highly efficient photocatalysts to address the problem of clean renewable energy applications.