1-Methyl-2-[(E)-2,4,5-trimeth-oxy-styr-yl]pyridinium 4-meth-oxy-benzene-sulfonate monohydrate.

In the title compound, C(17)H(20)NO(3) (+)·C(7)H(7)O(4)S(-)·H(2)O, the cation exists in an E configuration with respect to the C=C bond and is twisted with a dihedral angle of 17.81 (8)° between the pyridinium and benzene rings. The benzene ring of the anion is almost parallel to the pyridinium ring [dihedral angle = 3.45 (9)°], whereas it is inclined to the benzene ring of the cation [dihedral angle = 17.62 (8)°]. The crystal structure is stabilized by O-H⋯O hydrogen bonds and weak C-H⋯O inter-actions which link the cations, anions and water mol-ecules into chains along the a axis. π-π inter-actions with centroid-centroid distances of 3.7751 (9) and 3.7920 (11) Å are also observed.