Recent emphasis has been directed on attaining the sustainable development goals by 2030. Given the significance of water and its numerous functions, the necessity for clean water is paramount. The inefficacy of many water treatment methods limits their extensive application. Consequently, it is imperative to devise an efficient and environmentally sustainable approach for transforming organic pollutants into non-toxic and innocuous substances. This research employed a green synthesis method from Tradescantia spathacea to successfully produce CuO nanoparticles. Fourier Transform Infrared (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Scanning Electron Microscopy, and Energy Dispersive X-Ray analysis were employed to characterize and elucidate the structural, morphological, and compositional properties of the synthesized nanoparticles. Furthermore, the synthesized particles were employed to decompose the harmful Bromocresol Green dye in the water. At a concentration of 1 g/l of catalyst and basic medium, the degradation rate accelerated to 90-100% under UV light after approximately 80 minutes. When the light was not present, the photocatalytic breakdown of bromocresol green using CuO nanoparticles was found to be about half as effective as when the light was present. The effectiveness of CuO nanoparticles that have been produced was maintained even after five cycles. Thus, the green synthesized catalysts were very practical, efficient, and stable.