A 2:1 co-crystal of 3,5-dibromo-4-cyanobenzoic acid and anthracene

The title co-crystal, C8H3Br2NO2·0.5C14H10, was self-assembled from a 2:1 mixture of the components in slowly evaporating dichloromethane. The molecules adopt a sheet structure parallel to (1-12) in which carboxy hydrogen-bonded dimers and anthracene molecules stagger in both dimensions. Within the sheets, six individual cyano acid molecules surround each anthracene molecule. Cyano acid molecules form one of the two possible R22(10) rings between neighboring cyano and bromo groups. Compared to the dichloro analog [Britton (2012). J. Chem. Crystallogr. 42, 851–855], the dihedral angle between the best-fit planes of acid and anthracene molecules has decreased from 7.1 to 0.9 (2)°