2-[(E)-2-(4-Ethoxyphenyl)ethenyl]-1-methylquinolinium iodide dihydrate

In the title compound, C(20)H(20)NO(+)center dot I(-)center dot 2H(2)O, the cation is almost planar (r.m.s. deviation = 0.038 angstrom) and exists in an E configuration. The dihedral angle between the quinolinium ring system and the benzene ring is 0.7 (4)degrees. In the crystal structure, the cations are stacked in an anti-parallel manner along [100] with pi-pi interactions between the pyridinium and ethoxybenzene rings [centroid-centroid distance = 3.678 (5) angstrom]. The cations, iodide anions and water molecules are linked together through O-H center dot center dot center dot O, O-H center dot center dot center dot I and C-H center dot center dot center dot I hydrogen bonds into a two-dimensional network parallel to (001).