Abstract <p>This study provides a comprehensive comparison of the structural, optical, and electrical properties of Mg-doped ZnO thin films synthesized using methanol and ethanol as solvents. X-ray diffraction analysis confirmed the hexagonal wurtzite structure for both cases, with a stronger c-axis orientation in ethanol-derived films. Notably, magnesium incorporation led to an increase in crystallite size, reaching 23 nm in methanol-based films. Morphological analysis using scanning electron microscopy (SEM) revealed dense, homogeneous, and smooth surfaces for both solvent-derived films. Optical characterization indicated a reduction in transmittance for ZnO films synthesized in methanol compared to ethanol-based films, alongside an increase in the energy band gap (ranging from 3.23 to 3.34 eV) as Mg concentration increased. Photoluminescence spectroscopy identified UV emission and defect-related peaks in the visible region at room temperature. Magnesium incorporation was further verified by energy-dispersive spectroscopy (EDS) and Fourier-transform infrared spectroscopy (FTIR). Electrical and photocurrent measurements demonstrated n-type semiconducting behavior with enhanced photoresponse sensitivity. The Seebeck coefficient showed a decreasing trend with increasing Mg doping, with methanol-derived films exhibiting a higher coefficient (−525 μV/K) compared to ethanol-derived films (−400 μV/K). Despite this, methanol-based films exhibited a higher carrier concentration at the same Mg doping level. Furthermore, photocatalytic performance was optimized with 9% Mg-doped ZnO films synthesized in methanol, leading to enhanced degradation efficiency under solar irradiation. These findings emphasize the combined influence of Mg doping and solvent choice on the functional properties of ZnO thin films, providing valuable insights for their potential applications in environmental remediation and energy-related technologies.</p> Graphical Abstract <p></p>