Roald Hoffmann has investigated both organic and inorganic substances, developing computational tools and methods such as the extended Hückel method, which he proposed in 1963. He also developed, with Robert Burns Woodward, rules for elucidating reaction mechanisms (the Woodward-Hoffmann rules). He also introduced the isolobal principle.
In 1981, Hoffmann received the Nobel Prize in Chemistry, which he shared with Kenichi Fukui "for their theories, developed independently, concerning the course of chemical reactions"
[Video] A Multidimensional Index of Greenness Presentation at the Molecular Frontiers Symposium in Stockholm 2012