In this work, nanosized Cu and Ni Schiff-base complexes, namely ahpvCu, ahpnbCu, and ahpvNi, incorporating imine ligands derived from the condensation of 2-amino-3-hydroxypyridine, with either 3-methoxysalicylaldehyde (ahpv) or 4-nitrobenzaldehyde (ahpnb), were synthesized using sonochemical approach. The structure and properties of the new ligands and their complexes with Ni(II) and Cu(II) were determined via infrared (IR), nuclear magnetic resonance (NMR), electronic spectra (UV-Vis), elemental analysis (CHN), thermal gravimetric analysis (TGA), molar conductivity (Λ_m), and magnetic moment (μ_eff). The combined results revealed the formation of 1:1 (metal: ligand) complexes for ahpvCu and ahpvNi and 1:2 for ahpnbCu. Additionally, CuO and NiO nanoparticles were prepared by calcination of the respective nanosized Cu/Ni complexes at 500 °C, and characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Significantly, the as-prepared nanosized Schiff-base Cu/Ni complexes and their oxides showed remarkable catalytic activity towards the selective oxidation of benzyl alcohol (BzOH) in aqueous H₂O₂/ dimethylsulfoxide (DMSO) solution. Thus, catalytic oxidation of BzOH to benzaldehyde (BzH) using both ahpvCu complex and CuO nanoparticles in H₂O₂/DMSO media at 70 °C for 2 h yielded 94% and 98% BzH, respectively, with 100% selectivity.