Experimental

R factor = 0.040; wR factor = 0.120; data-to-parameter ratio = 16.9. In the title compound, C16H16Cl2N4, the imidazole ring mean plane makes a dihedral angle of 70.01 (1) with the phenyl ring. The Cl atoms deviate by 0.0472 (6) and 0.0245 (8) Å from the plane of their attached benzene ring. In the crystal, molecules are linked via pairs of C—H N hydrogen bonds, forming inversion dimers. Related literature For applications of the pyrazine ring system in drug devel-opment, see: Du et al. (2009); Dubinina et al. (2006); Ellsworth et al. (2007); Mukaiyama et al. (2007). For background to the fluorescence properties of related compounds, see: Kawai et al. (2001); Abdullah (2005). For general background to the use of imidazole derivatives as drugs, see: Dooley et al. (1992); Jackson et al. (2000); Banfi et al. (2006). For related structures, see: Ouzidan et al. (2011); Nasir et al. (2010)