Our research group is interested in the magnetic properties of matter; firstly, as a most important means of understanding the electronic structure of materials; and secondly, as a probe of some of their most exciting chemical and physical properties. As an example, we are studying the magnetic properties of free radicals formed from aromatic organic compounds with electron spin resonance in the hope of elucidating the mechanism of the carcinogenicity of these compounds. In addition, studies of transition metal ions in catalysts, high temperature superconductors, and photoacoustic crystals are beginning. Our experimental studies of these materials are carried out primarily with electron spin resonance spectroscopy, but also with electronic absorption spectroscopy and magnetic susceptibility measurements. Theoretical studies are done with a variety of molecular orbital calculations.