This invention relates to a multifunctional nanocomposite comprising at least two components (a).a superparamagnetic component of Fe3O4 nanoparticles (b) a semiconducting component of ZnO;wherein,the superparamagnetic component (a) comprising Fe3O4 nanoparticles are embedded into the porous network of semiconducting component (b) comprising ZnO nanoassembly thereby forming Fe3O4-ZnO magnetic semiconductor nanocomposites (MSN). This invention also relates to a method of synthesizing the Fe3O4-ZnO magnetic semiconductor nanocomposites.