Herein, we synthesized a Cu2O and Co3O4 incorporation with MoS2 to produce MoS2/Co3O4/Cu2O nanocomposites by facile sonication assisted hydrothermal methods. The phase structure and elemental composition of MoS2/Co3O4/Cu2O nanocomposites were investigated using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) morphology studies confirm that MoS2/Co3O4 nanostructure self-assembles in a mixed nanosheet configuration after the introduction of Cu2O. The synthesized samples were used as new types of Pt-free counter electrodes (CE) for DSSCs. Among all, the DSSCs based on the MoS2/Co3O4/Cu2O CE yields a maximum power conversion efficiency of 3.68 % (Jsc = 8.2 mA cm−2, Voc = 0.71 mV and FF = 0.629 %) under the standard AM 1.5 G illumination, which is 2.5 times higher than that of pure MoS2. To assess the photocatalytic activity, prepared samples were used to suppress methylene blue (MB) and rhodamine B (RhB) dye under UV–visible light irradiation. The MoS2/Co3O4/Cu2O nanocomposites had the highest photocatalytic degradation efficiency of all the samples. It increased degradation efficiency from 43 % to 91 % for MB dye after 100 minutes, and from 47 % to 92 % for RhB dye after 90 minutes. Scavengers test analysis proved that the superoxide radical (•O2−) play a major role in the MoS2/Co3O4/Cu2O photocatalytic system. After four consecutive photocatalytic cycles, the crystal structure and surface morphology of the MoS2/Co3O4/Cu2O nanocomposites used in the 4th cycle were more stable, and this was confirmed by SEM, EDAX and XRD studies. The broader significance of these findings provides a straightforward approach for synthesizing a low-cost and high-efficiency MoS2/Co3O4/Cu2O nanocomposite for CE in DSSC photovoltaic cells and facilitates organic pollutant removal through photocatalytic applications.