Cover illustration: A packing diagram for polymorph (Ib) of 1,4-dibromo-2,5-dimethylbenzene, viewed perpendicular to (001). The molecules are depth-cued; molecules with thicker bonds are nearer the viewer. C-HBr hydrogen bonds are represented by thin dashed lines and Br interactions by thick dashed lines. For the sake of clarity, the methyl H atoms have been omitted. See Jones & Kus [Acta Cryst. (2011), C67, o131-o133].