Considerable work is being carried out recently to develop nanomaterials which can act as photocatalyst under sunlight. In the present study, ZnO@CuS core-shell nanocomposites were synthesized and their photocatalytic activity has been investigated. The nanocomposites were prepared by thermal decomposition of a single molecular precursor, cyclo-tri-μ-thioacetamide-tris(chlorocopper(I)) complex ([Cu₃TAA₃Cl₃]), in the presence of ZnO nanorods in diphenyl ether at 200 °C. The effect of reaction time and precursor concentration on copper sulfide shell formation have been investigated. The ZnO@CuS core-shell nanocomposites were characterized using different techniques such as XRD, FE-SEM, TEM, FT-IR, UV-Vis, DRS and XPS. As compared to bare ZnO nanorods, the ZnO@CuS nanocomposites show better photocatalytic activity towards degradation of congo red in an aqueous solution under sunlight.