In this article, the basic principles of neutron diffraction and neutron depolarization are presented along with the results of some important magnetic materials. In particular, the recent results. of the rare earth based high magnetocaloric effect materials, semi-Beusler spintronics alloys, molecular magnets, layered spin system, and core-shell type magnetic nanoparticles have been described. The usefulness of the neutron diffraction and neutron depolarization techniques to understand structural and magnetic properties is brought out.