The use of various plant materials for the bio synthesis of metal oxide nanoparticles follows the principles of green chemistry since it minimizes the amount of chemicals used. In the present work, ZnO and Ag doped ZnO nanoparticles were synthesized utilizing aqueous leaf extract of Ficus benghalensis. The aqueous leaf extract was screened qualitatively for the presence of chemical constituents. The nanoparticles ZnO, green modified ZnO and Ag doped ZnO were characterized by X-ray diffraction (XRD), FT-IR, EDAX and Scanning Electron Microscope (SEM). The optical properties were studied using UV-Vis-DRS spectroscopy and a bathochromic shift is observed in the band gap energy of synthesized Ag doped ZnO. From XRD, the particle size of the ZnO, green modified ZnO and Ag doped ZnO nanoparticles was found to be 36, 39 and 53 nm respectively. Photodegradation of crystal violet dye was studied by UV-Visible spectroscopy. The degradation ability of the surface modified ZnO was found to be more efficient than that of bare ZnO and green modified ZnO nanoparticles. The photocatalytic reactions obeyed pseudo-first-order kinetics according to Langmuir- Hinshelwood model. The reuse of nanoparticles for photocatalytic activity was also studied.