Bis{4-[(E)-2-(1H-indol-3-yl)ethen-yl]-1-methyl-pyridinium} 4-fluoro-benzene-sulfonate nitrate 0.25-hydrate.

In the title compound, 2C(16)H(15)N(2) (+)·C(6)H(4)FO(3)S(-)·NO(3) (-)·0.25H(2)O, the two cations are nearly planar, with dihedral angles of 1.34 (14) and 4.6 (2)°, respectively, between the pyridinium and indole rings. The cations each adopt E configurations with respect to the C=C bonds and are inclined to each other with a dihedral angle of 77.66 (5)°. The ethenyl group of one cation is disordered over two sites with occupancies of 0.685 (12) and 0.315 (12), and the sulfonate group of the 4-fluoro-benzene-sulfonate anion is also disordered with occupancies of 0.535 (10) and 0.465 (10) for the two sets of O atoms. The anion is also inclined to the two cations, with dihedral angles between the mean planes of the benzene ring and the π-conjugated systems of the cations of 24.72 (11) and 79.83 (11)°. In the crystal structure, the cations are stacked in an anti-parallel fashion into columns approximately along the a axis and are further linked through the anions into a three-dimensional network via N-H⋯O and C-H⋯O inter-actions. The water mol-ecule forms O-H⋯O hydrogen bonds to the nitrate anion and C-H⋯π inter-actions are also observed.