The structure of the title compound, C25H23Cl2N5O.CH2Cl2, confirms the buckled nature of the dibenzodiazepine nucleus, with the central seven-membered heterocycle being in a boat conformation, the dihedral angle between the planes of the aromatic rings being similar to that found for the parent compound, clozapine and related structures. The piperazine ring displays an almost perfect chair conformation, with the methyl and chlorobenzimide groups assuming equatorial and axial orientations, respectively, at the cationic nitrogen site. At the other piperazine N atom, the dibenzodiazepine nucleus assumes an axial orientation. The relative positions of the dibenzodiazepine and piperazine ring systems is controlled by the planarity of the piperazine N atom in the amidine moiety.