In this paper, we explore a novel, one-step, economic, facile and eco-friendly route to synthesize in-situ tailored carbon nanostructures such as carbon nanorods (CNR) and carbon nanospheres (CNS) with reduced graphene oxide using tamarind extract (Garcinia Cambogia) by temperature dependent hydrothermal process under alkaline conditions for supercapacitor applications. FESEM analyses revealed the reduction of GO at 180 °C and formation of carbon nanostructures at relatively lower temperatures. The electrochemical performance of rGO and its carbon composites were evaluated for supercapacitor wherein it was observed that carbon composites exhibited a threefold increase in specific capacitance (70.06 F/g) when compared to rGO (27.35 F/g) which was attributed to the higher specific surface area offered by CNR and CNS. © 2017 Elsevier B.V.