In the title compound, C27H21ClN2O4, the mean planes of the two indole ring systems (r.m.s. deviations = 0.021 and 0.024 Å) are approximately perpendicular to one another, with a dihedral angle of 79.54 (12)°. The benzene ring is twisted with respect to the mean planes of the two indole ring systems at angles of 80.14 (15) and 86.30 (15)°. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds, forming inversion dimers with an R (2) 2(18) ring motif. The dimers are linked by a further N-H⋯O hydrogen bond, forming chains along [100]. There are intra- and inter-molecular C-H⋯π inter-actions present, the latter linking the chains to form a three-dimensional supra-molecular structure.
Keywords: C—H⋯π interactions; MRI contrast agent; N—H⋯O hydrogen bonds; bis-indolymethane; crystal structure; indole.