title: 1,1'-[(1E,11E)-5,8-Dioxa-2,11-diazo-nia-dodeca-1,11-diene-1,12-di-yl]dinaph-thal-en-2-olate.
abstract: The title compound, C(28)H(28)N(2)O(4), crystallizes in a zwitterionic form with deprotonated naphthol hy-droxy groups and protonated imine N atoms. The asymmetric unit contains one half-mol-ecule located on a twofold rotation axis. Intra-molecular N-H⋯O hydrogen bonds occur and the two bicyclic ring systems form a dihedral angle of 64.2 (1)°. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link the mol-ecules into layers parallel to the bc plane.
authors.forename: Yanju
authors.initials: Y
authors.lastname: Liu
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Cao
authors.forename: Meiju
authors.initials: M
authors.lastname: Niu