The hitherto elusive benzo[c]anthanthrenyl radical derivatives composed of seven fused six-membered rings are synthesized and isolated in the crystalline form, representing a laterally π-extended doublet open-shell graphene fragment compared to the phenalenyl and olympicenyl radical structures. X-ray crystallographic analysis revealed one-dimensional chain stacking with relatively close intermolecular contacts, which is an important precondition for achieving single-component conductors. The magnetic, optical, and redox properties are investigated in the solution phase. In combination with the good stability, such open-shell molecular systems have potentials as functional electronic materials.