The development of eco-friendly nanomaterials has gained significant attention due to increasing environmental concerns associated with conventional chemical synthesis. This study focuses on the green synthesis of copper oxalate nanopowder using plant extracts as natural reducing and stabilizing agents. Plant-derived phytochemicals such as flavonoids, phenolics, and proteins facilitate nanoparticle formation under mild conditions. The synthesized nanopowder was characterized using basic analytical techniques including UV–Visible spectroscopy, pH measurement, conductivity analysis, viscosity studies, and flame photometry. The results confirmed successful formation of copper oxalate nanoparticles, indicated by characteristic spectral features and stable physicochemical properties. The green synthesis approach proved to be cost-effective, safe, and environmentally benign. The study highlights the potential of plant-mediated synthesis for developing sustainable nanomaterials and their possible applications in catalysis, environmental remediation, and material science.