Diethyl 7,7'-di-chloro-4-oxo-4H-[1,4'-bi-quinoline]-3,3'-di-carboxyl-ate.

In the title compound, C24H18Cl2N2O5, the quinoline and quinolinone moieties are nearly perpendicular to each other, forming a dihedral angle of 82.36 (3)°. In the crystal, mol-ecules form a halogen bond between a Cl atom of a quinolinone moiety and the N atom of the quinoline moiety of the inversion equivalent [Cl⋯N = 3.106 (3) Å]. The mol-ecules also form two kinds of C-H⋯O hydrogen-bonded centrosymmetric inversion dimers, making chains along the c-axis direction which are further inter-linked by the halogen bonds into layers parallel to the bc plane.