Supercapacitors have gained significant attention from scientists due to their wide range of applications in energy storage devices. However, searching for abundant and eco-friendly materials on earth is still necessary while preserving their outstanding performance. Herein, cobalt molybdenum sulfide-graphitic carbon nitride (CoMoS4/g-C3N4) nanocomposite was synthesized to explore an exceptional electrode material for energy and photocatalytic applications. The structural analysis, vibrational modes, and porosity within the CoMoS4/g-C3N4 nanocomposite were studied by XRD, Raman, and SEM. The direct energy band gap decreased from 2.54 to 2.44 eV along with the increased ratio of CoMoS4 in the nanocomposite. The electrochemical measurements of CoMoS4/g-C3N4 nanocomposite exhibited an excellent specific capacitance (Cp) of 3675 F/g at 1 mV/s and 3150 F/g at 2.5 A/g with noticeable specific energy density (Eg) of 109.4 Wh/kg, high power density (Pd) of 625 W/kg and retain high capacitance (88 % of its initial value) even after 4000 cycles. Furthermore, the photocatalytic results revealed that high photodegradation efficiency (97.85 %) was attained against methyl orange (MO) dye under UV light irradiation. Prepared electrode materials are promising materials for next-generation energy storage and environmental applications.