2-[(E)-4-(Diethyl-amino)-styr-yl]-1-methyl-pyridinium iodide.

In the title compound, C(18)H(23)N(2) (+)·I(-), the cation exists in the E configuration with respect to the ethenyl C=C bond. The pyridinium and benzene rings are nearly coplanar, making a dihedral angle of 4.63 (7)°. The two ethyl groups of the diethyl-amino substituent point in opposite directions with respect to the benzene plane. In the crystal, the cation and the iodide anion are linked by a weak C-H⋯I inter-action. The cations are stacked in an anti-parallel manner along the a axis by a π-π inter-action with a centroid-centroid distance of 3.5262 (9) Å. The crystal structure is further stabilized by C-H⋯π inter-actions.