(E)-4-Allyl-2-[(2-hydroxy-phen-yl)iminiometh-yl]-6-methoxy-phenolate.

The title compound, C(17)H(17)NO(3), crystallizes in a zwitterionic form with cationic iminium and anionic enolate groups. The zwitterion exists in a trans configuration about the C=N bond. The dihedral angle between the two benzene rings is 13.42†(7)°. The meth-oxy group is almost coplanar [C-O-C-C = 2.1†(2)°] with the attached ring whereas the allyl unit is oriented at a dihedral angle of 67.9†(1)°. An intra-molecular N-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, the mol-ecules are linked into zigzag chains along [010] by O-H⋯O hydrogen bonds. In addition, weak C-H⋯π inter-actions are observed.