Nyctanthes arbor-tristis L. (Oleaceae), commonly known as harsingar, is a plant with potential medicinal properties. The plant was used in traditional folk medicine and as a pharmacological activity. The present study reports a rapid and eco-accommodating technique to synthesize silver nanoparticles AgNPs with low cost and with no need to heat, using aqueous extracts of N. arbor-tristis L. Phytochemical analysis was conducted to detect the existence of alkaloids, flavonoids, saturated sugar, saponins, glycosides, steroids, tannins, terpenoids, and proteins in the plant. A color change observed in the test confirmed the synthesis of AgNPs. SEM, XRD, EDX, FTIR, and UV – Visible spectrophotometer (DLS) were used to characterize the synthesized AgNPs. The antibacterial potential of AgNPs was further tested against different bacterial strains such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Klebsiella pneumonia displayed by finding the maximum zone of inhibition observed against S. typhi of 24.6 mm, S. aureus 21.6±0.57 mm, P. aeruginosa 19 mm, K. pneumonia 17 mm and E. coli 15.3±0.57 mm. Furthermore, the synthesized AgNPs were also exhibited as anticancer properties against MDA-231 cell line Human Breast cancer cell line which was determined dose dependent manner and their concentration of 2.5 to 30 μg/mL respectively, and noted the inhibitory range at 30 μg/mL of its concentration, which was further tested in high inhibitory effect on their leaf extract high concentration in cytotoxic, bactericidal experiments.