2-[(E)-2-(1H-Indol-3-yl)ethen­yl]-1-methyl­pyridinium 4-chloro­benzene­sulfonate

In the title compound, C(16)H(15)N(2) (+)·C(6)H(4)ClO(3)S(−), the cation exists in an E configuration with respect to the central C=C bond and is approximately planar, with a dihedral angle of 2.95 (5)° between the pyridinium and indole rings. The mean plane of the π-conjugated system of the cation and the benzene ring of the anion are inclined to each other at a dihedral angle of 69.65 (4)°. In the crystal packing, the cations are stacked in an anti­parallel manner along the a axis, resulting in a π–π inter­action with a centroid–centroid distance of 3.5889 (7) Å. The anions are linked into a chain along the a axis by weak C—H⋯O inter­actions. The cations are linked with the anions into a three-dimensional network by N—H⋯O hydrogen bonds and weak C—H⋯O inter­actions. There are also short O⋯Cl [3.1272 (10) Å] and C⋯O [3.1432 (14)–3.3753 (14) Å] contacts. The crystal structure is further stabilized by C—H⋯π inter­actions.