Zwitterionic 1-{(E)-[(2-methyl-phen-yl)iminium-yl]meth-yl}naphthalen-2-olate.

The title Schiff base, C18H15NO, crystallizes in its zwitterionic form and an N—H⋯O hydrogen bond closes an S(6) ring. The dihedral angle between the aromatic ring systems is 36.91 (10)°. Weak aromatic π–π stacking occurs in the crystal [minimum centroid–centroid separation = 3.7771 (15) A].