BaHfS3 is a Transition Metal Chalcogenide Perovskite (TMCP) with an experimentally measured bandgap of 2.06 eV. Lowering its bandgap could make BaHfS₃ a promising candidate for use as a solar cell absorber material. In this study, we perform a DFT-based first principles investigation to explore the bandgap tuning in BaHfS3 through substitutional alloying. The d-block element Hf is switched with different percentages of Ti atoms and the resulting variations in bandgap and optoelectronic properties are thoroughly examined. Our calculations reveal that the bandgap of BaHf1-xTixS3 decreases from 2.0 eV to 1.2 eV as the Ti proportion (x) increases from 0 to 0.5. Corresponding changes in the material’s optical properties are also observed. This work highlights the possibility of tailoring optoelectronic properties of BaHfS3 with substitutional alloying, enabling us to optimize the material’s properties for specific applications.