<p>Ruthenium (Ru) incorporation represents an effective strategy for tuning the optoelectronic properties of titanium dioxide (TiO₂) for solar energy conversion applications. In this study, Ru-doped TiO₂ samples with varying dopant concentrations (0–5%) were synthesized in both thin-film and pellet forms. Pure and Ru doped thin films have been deposited on glass substrates by the spin coating method. Samples were systematically investigated to elucidate the influence of Ru on their structural, morphological, electrical and optical properties. X-ray diffraction (XRD) confirmed retention of the anatase phase, with slight variations in crystallite size and lattice strain upon doping. Scanning electron microscope (SEM) images show an increase in dense agglomerated clusters composed of fine particles with increasing Ru content. X-ray photoelectron spectroscopy (XPS) revealed the formation of Ti³⁺ states and oxygen vacancies, indicating modification of the local electronic environment. Electrochemical Impedance spectroscopy (EIS) demonstrated thermally activated conduction and non-Debye relaxation behavior, consistent with defect-mediated charge transport. Optical measurements showed a progressive redshift of the absorption edge and energy bandgap (Eg) narrowing from 3.20&#xa0;eV (undoped) to 2.90&#xa0;eV (5% Ru-doped), attributed to defect-induced intermediate states and band tailing effects. The enhanced visible-light absorption and tunable electrical response highlight the effectiveness of Ru doping as a defect-engineering approach. These findings provide insight into tailoring TiO₂ properties for improved performance in dye-sensitized solar cells (DSSCs) and related optoelectronic applications.</p>