In the present study, a eco-friendly, low cost and biocompatible route to synthesize the NiNPs, has been proposed using the Pyrus calleryana (Callery pear) leaves extract, which is comprised of polyphenols, flavonoids and reducing sugar, which act as an excellent reducing and stabilizing agent. The as prepared NiNPs were characterized by various methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIF), atomic force microscopy (AFM), and UV-Vis spectroscopy. XRD proved crystalline tetragonal structure of NiNPs and SEM and AFM showed the homogeneous distribution of nanoparticles with particlesized ranging between 18.75 - 32.43 nm. Functional groups (hydroxyl, carbonyl and aromatic rings) essential in nanoparticle stabilization were characterized with FTIR, whereas UV-Vis, evidenced an absorption peak at ∼380 nm, corresponding to NiNP formation. The phytochemical composition of the P. calleryana extract was an important factor for nanoparticle synthesis as polyphenols and flavonoids served to nucleate and prevent aggregation. This research featured the potential of plant-assisted synthesis as a green approach for nano-synthesis and provided structural and functional attributes of bio-mediated NiNPs for environmental and industrial applications.