This study uses an environmentally friendly approach to explore a new synthetic pathway for Schiff bases and their metal complexes. A new Schiff base ligand (C) was synthesized by reacting 7-aminodeacetoxycephalosporanic acid with benzaldehyde. The resulting Schiff base was then reacted with three transition metal (Zn, Fe, and Mn) nanoparticles facilitated by ethanolic extracts from three different plant leaves (Moringa oleifera, Azadirachta indica, and Trigonella foenum-graecum) to formulate environmentally friendly nanometal complexes (C1 to C9), which were subsequently evaluated for their anti-bacterial and antioxidant activities. These complexes exhibited crystallite sizes in the range of 7.24-64.24 nm. Structural, compositional, and elemental analysis of the Schiff base ligand and its metal complexes was carried out using FTIR, 1H-NMR, 13C-NMR, XRD, and SEM-EDX, which confirmed the integration of metal moieties within non-uniform sheet-like nanostructures. The thermal properties of all synthesized samples were quantified via TGA, which provides a comprehensive understanding of the thermal properties and decomposition mechanisms of Schiff bases and their metal complexes. Assessment of the antibacterial activity of the Schiff bases and their complexes revealed strong action against both gram-positive (Staphylococcus aureus and Stenotrophomonas maltophilia) and gram-negative (Pseudomonas aeruginosa and Xanthomonas campestris) strains. The prepared samples showed antioxidant activity in the following order: C4 > C5 > C6 > C1 > C2 > C3 > C7 > C8 > C9. Most of the samples, particularly the Zn-complex derived from Moringa, exhibit promising potential for pharmaceutical applications.