2-[(E)-2-(1H-Indol-3-yl)ethen-yl]-1-methyl-pyridinium 4-bromo-benzene-sulfonate.

In the title compound, C(16)H(15)N(2) (+)·C(6)H(4)BrO(3)S(-), the cation exists in the E configuration and is essentially planar with a dihedral angle of 3.10†(5)° between the pyridinium ring and the indole ring system. The π-conjugated planes of the cation and the anion are inclined to each other at a dihedral angle of 64.32†(4)°. In the crystal structure, the cations are stacked in an anti-parallel manner along the a axis. The anions are linked into a chain along the a axis. The cations and the anions are linked into a three-dimensional network by N-H⋯O and weak C-H⋯O hydrogen bonds. The crystal structure is further stabilized by C-H⋯π inter-actions. A π-π inter-action between the five-membered heterocyclic ring of the indole system and the pyridinium ring is also observed with a centroid-centroid distance of 3.5855†(7)†à .