The whole molecule of the title Schiff base compound, C28H28N2O2, is generated by inversion symmetry. It is formed from two units of ortho-hy-droxy-naphthaldehyde bridged with 1,6-di-amino-hexane. The N atoms are protonated and, thus, the structure is a bis-zwitterionic compound in the solid state. The zwitterion shows strong intra-molecular N-H⋯O hydrogen bonds between the iminium N and the naphthaleno-late O atoms.
Keywords: 1,6-diaminohexane; 2-hydroxy-1-naphthaldehyde; crystal structure; elemental analysis.; hydrogen bonding.