June 2014 issue
Cover illustration: The compound C20H14N4 is a new polymorph of the previously reported structures, which were orthorhombic, space group Pbca [Bei et al. (2000). Acta Cryst. C56, 718-719] and monoclinic, space group P21/c [Dudd et al. (2003). Green Chem. 5, 187-192]. The crystal structures of two solvated forms of the same molecule have also been reported; the dimethylformamide monosolvate, monoclinic space group P21/n [Wu & Hu (2009). Acta Cryst. E65, o522] and the methanol monosolvate, triclinic space group P-1 [Su et al. (2011). Acta Cryst. E67, o90]. In all four crystal structures the 1,4-bis(1H-benzimidazol-2-yl)benzene molecules possess inversion symmetry. In the present monoclinic polymorph, space group P21/c, this is not the case, as the title compound crystallizes with two independent molecules in the asymmetric unit. See: Fu, Liang, Liu & Zhu [Acta Cryst. (2014). E70, o699].