Figure 1.

Molecular structures of a) seven non‐alternant isomers of pyrene, and b) benzo‐extended cyclohepta[def]fluorene derivatives in this work: benzo[5,6]cyclohepta[1,2,3,4‐def]fluorene (1), indeno[6,7,1,2‐ghij]pleiadene (2) and benzo[4,5]indeno[6,7,1,2‐ghij]pleiadene (3). Spin nature of ground state (S) is anticipated by the extension of Ovchinnikov rule (S=(N _s−N _u)/2, N _s and N _u represent number of starred and unstarred atoms, respectively). Clar's sextet is donated by cyan‐colored benzenoid ring in the resonance structure.