<p>This study investigates the effects of tailoring precursor concentrations on the properties of Copper Tin Sulfide (CTS) thin films synthesized using the Successive Ionic Layer Adsorption and Reaction method. Varying copper chloride concentrations (0.03, 0.04, 0.05&#xa0;M) optimizes the deposition conditions for CTS thin films, resulting in improved structural, optical, and electrical properties. The films exhibit a crystalline structure with crystallite sizes ranging from 90.85 to 114.49&#xa0;nm and dislocation densities between 0.76 × 10¹⁴ and 1.23 × 10¹⁴&#xa0;m⁻². The optical properties show high absorption coefficients in the ultraviolet region and wide bandgap energies ranging from 2.26 to 2.37&#xa0;eV. The electrical properties are influenced by precursor concentrations, with resistances ranging from 2.2 × 10¹⁰ to 3.7 × 10¹⁰&#xa0;Ω and conductances between 2.7 × 10^–11 and 4.6 × 10^–11&#xa0;Ω⁻¹. The CTS04 sample showcases desirable characteristics, including a high bandgap energy, pronounced absorption in the UV region and semiconductor behavior. These findings contribute to developing cost-effective solar cells and renewable energy sources, paving the way for a sustainable energy future.</p>