In this study, silver oxide nanoparticles (Ag 2 O-NPs) were synthesized from silver nitrate using green amaranth leaf extract as reducing agent. The degradation of caffeine and inactivation of Escherichia coli by Ag 2 O-NPs was studied under compact uorescent lamp illumination irradiation. Apart from that, the antibacterial and antioxidant activities of Ag 2 O-NPs were also examined. Synthesized Ag 2 O-NPs were shaped like monodispersed husk, and cubic structured with surface area and average particle size was detected to be 100.21 (m 2 /g) and 81 nm respectively. Antioxidant e cacy of the Ag 2 O-NPs was evaluated using 1, 1-diphenyl-2-picrylhydrazyl and 91% inhibition was achieved with 100 µg Ag 2 O-NPs.Bacteriocidic propensity of Ag 2 O-NPs was examined against the S. aureus and P. aeruginosa by disc diffusion, minimum inhibitory concentration (MIC), Live and dead assay. It was observed that the NPs have higher bactericidal effect on Gram-negative as compared to Gram-positive bacteria. Up to 96% photocatalytic inactivation of E. coli was achieved using 30 µg/mL of NPs, Photocatalytic degradation of caffeine (50 ppm initial concentration) was observed to be 99% at pH 9 in 15 h using 50 mg/L of Ag 2 O NPs. These results indicate that Ag 2 O NPs can be employed in environmental applications like harmful bacteria inactivation and organic pollutants degradation.