1-[4-(Diaminomethyleneaminosulfonyl)phenyliminiomethyl]-2-naphtholate N,N-dimethylformamide disolvate

The asymmetric unit the title compound, C18H16N4O3S·2C3H7NO, contains a molecule in a zwitterionic form with a deprotonated hydroxyl group and an iminium group, and two dimethylformamide solvent molecules. The dihedral angles of the guanidine group and the naphthyl ring system with respect to the central benzene ring are 76.04 (7) and 3.45 (9)°, respectively. The conformation of the molecule may be influenced, in part, by two intramolecular hydrogen bonds, while in the crystal structure, intermolecular hydrogen bonds form one-dimensional chains along [010].