Exploiting cost-effective Pt-free counter-electrode materials with low-cost synthesis and high catalytic activity is crucial for dye-sensitized solar cells. This paper introduces the sol-gel drop casting approach for preparing cobalt sulfide-doped graphene (CoS/rGO). The cobalt sulfide-doped graphene nanocomposite exhibits electrocatalytic properties comparable to conventional Pt electrodes as the counter electrode (CE) in DSSCs. Cobalt sulfide-doped graphene nanocomposites were synthesized via a direct sol-gel approach as a low-cost substitute for Pt. Characterization using X-ray diffraction, scanning electron microscopy/energy-dispersive/transmission electron microscopy, and UV-Vis spectroscopy shows the successful formation of Cobalt sulfide-doped graphene nanocomposites. The band gap energy of Cobalt sulfide-doped graphene is 3.05 eV, which is lower than rGO (3.252 eV), due to enhanced light absorption in the visible range imparted by rGO. The open circuit voltage is 0.75 V, the short circuit current density is 17.88 mA/cm2, and the fill factor is 0.527. Under the illumination of AM 1.5 simulated solar light (100 mW cm−2), the DSSC based on the proposed CoS/rGO CE achieved an efficiency of 7.0759 %.