(E)-1-(3-Chloro-phen-yl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium.

The title zwitterion,, C16H11ClN2O, is approximately planar, the dihedral angle between the benzene ring and naphthalene ring system is 1.55 (13)°; an intra-molecular N-H⋯O hydrogen bond stabilizes the planar conformation. In the crystal, π-π stacking between the benzene ring and the naphthalene ring system of adjacent mol-ecules links the mol-ecules into supra-molecular chains running along the b axis, the centroid-centroid distance being 3.

Bis{1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olato}copper(II).

The Cu(II) atom in the title compound, [Cu(C16H10ClN2O)2], is located on an inversion center and is tetra-coordinated by two N and two O atoms from two bidentate 1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a square-planar complex. In the crystal, mol-ecules are linked via weak C-H⋯O and C-H⋯Cl hydrogen bonds, forming chains propagating along [010]. There are also π-π inter-actions present involving adjacent naphthalene rings [centroid-centroid distance = 3.