Abstract A novel approach for the synthesis of magnetic iron oxide nanoparticles using concentrated solar radiation (CSR) is being reported first time. Magnetic iron oxide nanoparticles were prepared by photochemical oxidation of Fe (II) using a renewable source of energy which is a greener aspect of this method. The average particle shape and size of the nanoparticles was determined with the help of Transmission electron microscopy (TEM) which were found to be spherical with an average size of 8.81 (±3) nm. The new greener methodology with the single precursor has been developed for the synthesis of magnetic iron oxide nanoparticles (Fe3O4). This technique is relatively pollution free, environmentally benign and is a green approach for the nanomaterials synthesis.