The first green reduction of graphene oxide (GO) using cashew leaf extract as biorenewable reducing agents containing water soluble tannins and gallic acid is reported herein. The synthesized rGO has been well characterized by TEM, SEM, XRD, FTIR, Raman, UV-vis spectroscopy, and cyclic voltammetry. A catalytic probe for electro-/chemical reduction of a nitro group into an amino group in an aqueous medium was also performed successfully.