<p>Enhancing the structural, optical and electrical properties of CuO thin films is crucial for their effective integration into modern optoelectronic devices. In this study, tin (Sn) and iron (Fe) co-doped CuO thin films were fabricated on ultrasonically cleaned glass substrates using the sol-gel spin-coating technique, with varying dopant concentrations to optimize their properties. Post-annealing characterization revealed that all samples retained a polycrystalline monoclinic CuO structure, as confirmed by X-ray diffraction (XRD). The crystallite size increased from 19&#xa0;nm to 24&#xa0;nm upon (Sn, Fe) co-doping, accompanied by a decrease in dislocation density from 2.34 × 10^− 3 nm^− 2 to 1.80 × 10^− 3 nm^− 2_, indicating improved crystallinity. Scanning Electron Microscopy (SEM) analysis showed increased surface uniformity following dopant incorporation. Optical analysis revealed that co-doping significantly decreased transmittance while enhancing visible light absorption. The (1.5 wt% Sn + 0.5 wt% Fe): CuO film maintained a high absorption coefficient (&gt; 10⁵ cm⁻¹) and exhibited a reduced optical band gap of 1.43&#xa0;eV, enhancing the light-harvesting capability. Hall effect measurements demonstrated that the film co-doped with 1.5 wt% Sn and 0.5 wt% Fe exhibited the lowest resistivity (28.5 Ω·cm), highest electrical conductivity (0.035&#xa0;S/cm), and maximum carrier concentration (6.85 × 10¹⁷ cm^− 3), though with a reduced carrier mobility (0.304 cm²/V·s). However, further increase in Fe concentration (≥ 1 wt%) led to structural degradation under identical annealing conditions. Overall, the optimized 1.5 wt% Sn and 0.5 wt% Fe co-doped CuO thin film exhibits superior structural integrity, optical and electrical properties, demonstrating strong potential for application in future optoelectronic and photovoltaic devices.</p>