In this work we describe a novel and eco-friendly, room temperature synthesis of magnetic iron oxide nano particles (MIONPs) utilising the fruit extract of Cynometra ramiflora, an inedible fruit waste. The synthesised nanoparticles were characterised by various methods X-Ray Diffraction results confirmed the presence of Fe2O3 nanoparticles. The surface area of the MIONPs was determined as 107.97 m(2)/g by BET analysis. The zero point charge of the nanoparticles was estimated as 8.1. The FTIR analysis indicated the presence of various functional groups of phytochemicals of Cynometra ramifiora fruit extract which were responsible for the formation of nanoparticles. The photocatalytic ability of the nanoparticles was demonstrated by the degradation of methylene blue dye under sunlight irradiation. The reusability and the stability of the MIONPs were tested for five cycles which ascertained the potential photocatalytic activity. Thus, these nanoparticles could play a vital role in the environmental catalytic remediation of polluted water.