The present work reports the green synthesis of Ag-doped NiO–ZnO nanocomposites using the aqueous leaf extract of Aegle marmelos through a simple and scalable co-precipitation method. The utilisation of plant extract as a natural reducing and stabilising agent not only avoids the use of hazardous chemicals but also promotes the eco-friendly fabrication of biocompatible nanostructures. The prepared nanocomposites were characterised by (XRD) confirmed the formation of crystalline phases of NiO and ZnO with successful Ag incorporation, and the crystallite size was calculated as 8 nm – 30 nm using the Scherrer equation. The biological activity of the nanocomposites was assessed against representative Gram-positive bacteria like Streptococuus mutants and Gram-negative bacteria like E. Coli and fungal strains like Yeast Candida albicans. The Ag-doped samples exhibited significantly higher antibacterial and antifungal activity compared to undoped NiO–ZnO, highlighting a synergistic mechanism involving silver ion release, reactive oxygen species generation, and disruption of microbial cell walls. These findings clearly establish that silver doping not only enhances the structural and optical features of NiO–ZnO but also greatly improves its antimicrobial efficiency.

Keywords: Coprecipitation; Nanocomposite; XRD; Green Synthesis;