The principle, capabilities, advantages and limitations of the optically detected magnetic resonance (ODMR) technique will be briefly described. The ability of the ODMR technique to provide important information on physical properties of semiconductor thin films and layered structures will be highlighted. These include chemical identification, electronic and geometric structures of defects, carrier recombinations, etc. The important role in providing valuable feedback for improvement of growth process and in engineering material properties for device applications will be demonstrated. Representative cases from Si/SiGe- and InP- based structures grown by molecular beam epitaxy will be discussed as examples. The most recent progress, on-going efforts and prospects in achieving unprecedently high spectral, time and spatial resolution of the ODMR technique, meeting the demands and challenges raised by the increasing miniaturization of future electronic and optoelectronic devices, will also be outlined.