Open-shell organic semiconductors are poised to enable new functions and applications ranging from electronics and optoelectronics to magneto-electronics. Here, we review strategies toward molecular magnets or spin–polarized magnetic organic semiconductors that encompasses incorporation of stable radical groups directly into the backbone of organic semiconductors or preparation of highly conjugated ladder-type molecules based on open–shell Kekulé–type structures to enable efficient spin delocalization/spin-transfer along the conjugation length. We briefly survey the history of this field, summarize recent developments, and set an outlook for the future.
