Two approaches have been pursued to construct bulk magnets by ordering spins of unpaired 2p-electrons of organic free radicals. One is an intermolecular approach based on the crystal design of stable radicals. The other consists of intramolecular alignment of spins in polyradicals having many unpaired electron. The two approaches progressed complementarily to establish unprecedented molecule-based magnets. The second approach by our research group developed polyradicals, polycarbenes and their supramolecular assemblies with metal ions into permanent magnets, thereby deepening the understanding of chemical bonds and opening a new horizon of developing new magnets with other functionality.


(Communicated by Hiroo INOKUCHI, M.J.A.)