A [4π+4π] intramolecular photocyclomer of 9‐anthroic anhydride: 5,6,11,12‐tetrahydro‐5,12;6,11‐di‐o‐­benzenodibenzo[a,e]cyclooctene‐5,6‐dicarboxylic anhydride

The title compound, C₃₀H₁₈O₃, was obtained by light irradiation of a di­chloro­ethane solution of 9‐anthroyl chloride and 9‐anthroic acid. The mol­ecules, which possess approximately mm2 local symmetry, are packed in columns, the oxy­genated moieties facing each other according to the symmetry of a monoclinic lattice. The space group of the crystal is P2₁/c, with a whole mol­ecule as the asymmetric unit. The structure is compared with those of similar dianthracene derivatives.