Mixed-ligand coordination complexes have attracted significant attention owing to their diverse structures, tunable properties, and potential applications in catalysis, sensing, and bioinorganic chemistry. In this study, a series of transition metal complexes incorporating bidentate Schiff base ligands and ancillary neutral donor ligands (such as pyridine and 1,10-phenanthroline) were synthesized and characterized. Magnetic susceptibility measurements were performed to elucidate their electronic configurations and geometry, while spectroscopic studies (UV–Visible, FT-IR, and electronic spectra) were used to investigate ligand coordination modes. The results revealed that the complexes exhibit octahedral or square-planar geometries depending on the metal ion, and their magnetic moments are consistent with predicted spin-only values. These findings highlight the role of ligand field effects in controlling the structural and magnetic behavior of mixed-ligand complexes.