<p>One of the most effective methods of promoting sustainable development and climate change mitigation is to reduce and convert carbon dioxide (CO₂). Photocatalysts based on CdS have been utilized for CO₂ reduction. After a number of modifications, the CdS-based materials were used to increase the photocatalytic effectiveness of CdS. A series of flower-like In-doped CdS microstructures were fabricated with different molar ratios of indium to further enhance the photocatalytic effectiveness. The phase structure, elemental speciation, and morphology of CdS and In-doped CdS were investigated using XRD, HRTEM, XPS, SEM–EDS, and FESEM. The characterization results were found to be in good mutual agreement, supported and endorsed reciprocally. After the inclusion of In over the CdS substrate, the band gap of In-doped CdS decreased from 2.26 to 2.17&#xa0;eV. In-doped CdS was used as a photocatalyst in distinct experimental sets for the conversion of Cr(VI) to Cr(III) and the reduction of CO₂ to CO and CH₄. As the molar ratio of In to CdS increased, the amount of CO generation increased from 7.5 to 14.67 mol/g. In-CdS produced a significant amount of CH₄ (2.81 mol/g) compared to pure CdS (0.2 mol/g). In-doped CdS had a higher rate of Cr(VI) reduction to Cr(III) (95.05%) than pure CdS (64.45%). The In-doped CdS can be used as multifunctional catalyst for effective CO₂ and Cr(VI) reduction.</p> Graphical abstract <p></p>