Maximum pollutants in the industrial and domestic waste water effluents from any sources include pathogens and organic chemicals, which can be removed before discharging into the water bodies. Methylene blue has been considered as one of the major water contaminated pollutants. Such pollutant is dominant in surface water and groundwater. It will cause irreversible hazards to human and aquatic life. Nanotechnology plays a major role in degrading such type of pollutant. In order to fulfill today's requirement, we have decided to handle the green synthesis of nanoparticles and its application by merging important fields like chemistry, environmental science, and biotechnology. Here our work emphasizes on the biological synthesis of SnO2 nanoparticles (SnO2 NPs) using the methanolic extract of Cyphomandra betacea (C.betacea), and it was confirmed by various characterization techniques such as UV-visible spectroscopy, FT-IR, XRD, SEM, particle size analyzer, zeta potential, and TEM. The obtained results stated that the synthesized SnO2 NPs were in rod shape with an average size of 21nm, which resulted in a product of nanobiotechnology. Further, we have utilized the environmental-friendly synthesized SnO2 NPs photocatalytic degradation of environmental concern methylene blue with first-order kinetics. In this paper, we have attempted to prove that secondary metabolite-entrapped SnO2 NPs are non-toxic to the environment.