Nanoparticles differ significantly from their bulk counterparts in terms of their characteristics, and they have a wide range of scientific uses. The use of green nanoparticles have received considerable attention. Recent advances in green nanomaterial production have made it possible to utilize these materials in catalysis. Many techniques have been applied to treat the textile wastewater. In the current study, Alizarin Red S dye is photocatalytically degraded utilizing green synthesized NiO nanoparticles derived from green tea extract. Utilizing techniques such as FT-IR, UV-Visible spectroscopy, EDAX, SEM, and XRD, the synthesized nanoparticles were examined. The morphology of the nanoparticle was studied using the SEM images. The XRD analysis was used to find the size of the crystal. The formula developed by Debye Scherer was used to determine the crystallite size. It was seen that the crystallite size was 29.75 nm. Using EDAX, the existence of Ni was verified. FT-IR analysis was used to find the functional groups present in the nanoparticle. According to morphological research, the nanoparticles are flake-shaped and have a larger surface area. Systematically the impact of many parameters on dye degradation, including catalyst dosage, dye concentration, and pH was examined. The findings showed that NiO can be used as a good nanocatalyst to degrade organic dyes. The kinetics of photodegradation were studied. Antibacterial and antifungal activities carried out on the synthesized nanoparticle and the precursor green tea shows that they have good activity over bacteria and fungi. The right selection of operating conditions allows to degrade the pollutant effectively.