Crystal structure and Hirshfeld surface analysis of a conformationally unsymmetrical bis-chalcone: (1E,4E)-1,5-bis-(4-bromo-phen-yl)penta-1,4-dien-3-one.

In the title bis-chalcone, C17H12Br2O, the olefinic double bonds are almost coplanar with their attached 4-bromo-phenyl rings [torsion angles = -10.2 (4) and -6.2 (4)°], while the carbonyl double bond is in an s-trans conformation with with respect to one of the C=C bonds and an s-cis conformation with respect to the other [C=C-C=O = 160.7 (3) and -15.2 (4)°, respectively]. The dihedral angle between the 4-bromo-phenyl rings is 51.56 (2)°. In the crystal, mol-ecules are linked into a zigzag chain propagating along [001] by weak C-H⋯π inter-actions. The conformations of related bis-chalcones are surveyed and a Hirshfeld surface analysis is used to investigate and qu-antify the inter-molecular contacts.