(E)-2-[4-(Dimethyl­amino)styr­yl]-1-methyl­quinolinium iodide sesquihydrate

In the title compound, C(20)H(21)N(2) (+.)I(−)·1.5H(2)O, the cation exists in the E configuration and is not planar. The dihedral angle between the quinolinium and dimethyl­amino­phenyl rings is 9.26 (6)°. The O atom of one of the solvent water mol­ecules lies on a twofold rotation axis. In the crystal structure, the cations form one-dimensional zigzag chains along the [001] direction. The cations are linked to water mol­ecules and iodide ions through weak C—H⋯O and C—H⋯I inter­actions, respectively. Water mol­ecules and iodide ions form O—H⋯O and O—H⋯I hydrogen bonds, which stabilize the crystal structure. A C—H⋯π inter­action is also present.