This book outlines the possibility of combining semiconducting and magnetic functionalities at nanoscale. The pure semiconducting clusters of Ge, C and ZnO have been investigated systematically using density functional theory. The magnetism in these nano-clusters has been incorporated by doping with 3d transition metals, p-block impurities (C, N and B) as well as by introducing point defects. The results have presented an alternate way of inducing magnetism by incorporating magnetic or non-magnetic impurities as dopant and co-dopant in Ge, C and ZnO clusters. The size dependent properties of nanoclusters and effect of point defects are additional factors which influence the magnetic properties of the Ge, C and ZnO clusters. The results of this work are supposed to provide guidelines for realization of spintronic based devices.