Semiconducting characteristics of antimony-based chalcogenides in the recent past gained the utmost attention for photovoltaic (PV) cells and photo electrochemical (PEC) hydrogen evolution. In the current research endeavour, a simple hydrothermal route has been employed to prepare polycrystalline Sb2S3 thin films. Under ideal temperature conditions of 120 °C, Sb2S3 films were prepared in an autoclave, varying the reaction times between 10:00 and 14:30 h with an interval of 30 min. Further heat treatment of the as-synthesized Sb2S3 thin films was carried out on an electric hot plate at 200 °C for 90 min. XRD analysis of heat-treated Sb2S3 films unveiled an orthorhombic crystal structure with (310) predominant plane. Consequently, the crystallite sizes, displayed improvement from ∼ 33 to 77 nm, with reaction periods for 10:00 to 13:30 h and decreased after that. The five distinct Raman modes were spotted at 155, 190, 236, 280, and 305 cm−1, further confirming the single-phase formation of Sb2S3 thin films. SEM and EDS analysis indicated conspicuous variations in surface morphology and stoichiometric ratios of antimony and sulfur elements. The Sb2S3 thin films deposited at 120 °C for 13:30 h are found to be nearly stoichiometric (Sb and S are 42.61 and 57.39 at. %). The resultant oxidation states were demonstrated to be (+3) and (−2) for antimony and sulfur respectively. All the thin films exhibited an optical absorption coefficient greater than 104 cm−1 with a direct energy band gap ranging between 1.43 and 1.61 eV. The Sb2S3 thin films deposited for 13:30 h have unveiled the highest photocurrent density of −0.27 mA/cm2, indicating a potential photocathode for hydrogen production.