The CZTS thin films have been deposited on Mo coated corning glass substrate via single-step electrodeposition technique followed by post-annealing treatment at 550˚C for 10 min in Ar-H2S atmosphere. The deposition potential effects on structural, optical, morphological, compositional, and photoelectrochemical (PEC) properties have been investigated through various tools such as x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), energy dispersive x-ray spectroscopy (EDS), UV-Visible spectroscopy, Raman spectroscopy, etc. XRD patterns, XPS, and Raman spectra confirm the formation of CZTS films with no trace of impurities and appreciable crystallinity. EDS analysis shows that high-quality CZTS films with Cu-poor and Zn-rich composition can be synthesized by varying deposition potential from -0.85 to -1.05 V. Formation of interconnected grains with an increase in grain size has been observed from FE-SEM analysis. The bandgap of films was found in the range 1.46-1.57 eV when the deposition potential was varied from -0.85 V to -1.15 V. Photoresponse characteristics show that photocurrent in CZTS films is due to cathodic surface reaction and the photoconductivity is of p-type. The photoelectrochemical impedance spectroscopy (PEIS) analysis showed CZTS film deposited at potential -1.15 V has the highest photocurrent activity. Based on the obtained results in the present study, one can infer that electrodeposited CZTS films can be a potential candidate for optoelectronic applications.