Herein, we report the MnS, CdS and MnS/CdS nanoparticles prepared by precipitation method. The as-synthesized particles were characterized using by scanning electron microscope, X-ray diffraction, UV-diffuse reflectance spectroscopy, photoluminescence, X-ray photoelectron spectroscopy and photoelectrochemical technique. MnS/CdS composite combination enhanced the optical, photocatalytic, and photoelectronic properties of the samples. Photocatalytic performances of the samples were evaluated under visible light irradiation. The photoelectrode activity of all samples was also investigated. MnS/CdS composites were found as efficient photocatalysts under visible light. The enhanced photocatalysis of the composites was attributed to the possible defect structure, high electron density of CdS and inhibition of electron/hole pairs as well as optimal content of CdS in the composite system. MnS/CdS composites must be evaluated for photocatalytic and photoelectrochemical activities with broader visible light range.