2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-methylbenzenesulfonate

In the title salt, C19H18NO2+·C7H7SO3−, the C=C double bond in the cation has an E configuration. The cation is not planar as the dihedral angle between the quinolinium and benzene ring systems is 14.74 (8)°. The anion is aligned approximately perpendicularly to the cation, with the benzene ring of the anion making dihedral angles of 89.98 (8) and 75.36 (10)° with the quinolinium and benzene ring systems of the cation, respectively. An intra­molecular O—H⋯O hydrogen bond between the hydr­oxy and meth­oxy groups generates an S(5) ring motif. The cations link with anions through weak C—H⋯O inter­action into cation–anion pairs along the b direction, and the adjacent pairs are further linked by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions into a three-dimensional network. The crystal is further stabilized by C—H⋯π inter­actions, and π–π inter­actions [centroid–centroid distances of 3.5236 (12) and 3.5337 (12) Å] are also observed.