BackgroundConsiderable research efforts have been dedicated to comprehensively evaluate the electrochemical and photocatalytic properties of newly synthesized metal sulfides.AimsThis research aims to determine the viability of using metal sulfide, MnS2:Ni9S8:Co3S4 thin film with excellent energy retention capacities and amazing photocatalytic activities.Materials & MethodsSingle source precursor method was utilized for the synthesis of metal sulfide. Furthermore, deposition of thin film was performed through physical vapour deposition route. Detailed characterization was done by using UV‐visible spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction crystallography and X‐ray photoelectron spectroscopy. Electrochemical investigation was done through cyclic and linear sweep voltammetry while competence of the thin film in degrading various environmental pollutants, including crystal violet dye, fuberidazole and phenol, was evaluated by photocatalytic degradation.Results & DiscussionA crystallite size of 47 nm with 86.5% crystallinity was found along with a 3.4 eV bandgap energy. Round‐edged cubical structures in the composite were seen. X‐ray photoelectron spectroscopy revealed core level peaks of Mn 2p, Ni 2p, Co 2p and S 2p. A specific capacitance of 590 Fg−1 was observed from the electrochemical analysis showing the presence of electroactive sites that allow for effective electrochemical processes. After 60 minutes of exposure to the thin film, phenol showed the slowest rate of degradation, whereas crystal violet and fuberidazole showed significant percentages of deterioration.ConclusionThe findings highlight MnS2:Ni9S8:Co3S4 thin film's adaptability as viable compound for addressing the critical concerns of storing energy, production, and environmental cleanup. These significant findings highlight the versatility of tri‐metal sulfide thin films, opening up avenues for further research and technological advancements.