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

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