Nowadays, heterogeneous catalysts are preferable to homogeneous catalysts to get more socioeconomic assistance due to multiple recycling. In the current study, CuO/PVA nanocomposites were synthesized via the chemical reduction method, followed by ultra-sonication. The synthesized nanocomposites were confirmed using different characterization techniques, such as X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy, dynamic light scattering, zeta potential, Fourier transform infrared spectroscopy, UV-Visible spectroscopy, and X-ray photoelectron spectroscopy. In order to verify their efficacy in the catalytic degradation, engineered CuO/PVA nanocomposites were used for the degradation of Rhodamine B dye in an aqueous medium. Finally, catalytic results exposed that copper oxide nanocatalyst showed an exceptional degradation, greater than 98% using a minimum catalyst dose of 150 mu g within 75 s using optimized parameters for NaBH4 (125 mu L) and Rhodamine B (0.01 M). To the best of our knowledge, this is the first study of Rhodamine B degradation by CuO/PVA nanocomposite as the catalyst. Certainly, the nanocatalyst presented here is more useful and realistic and hence can be suggested as an effective candidate for the successful degradation of complex dyes at the commercial level.