4-(2-Carb-oxy-vin-yl)pyridinium iodide.

In the crystal structure of the title salt, C(8)H(8)NO(2) (+)·I(-), the cations and anions are linked by bifurcated N-H⋯(O,I) hydrogen bonds. A near-linear O-H⋯I hydrogen bond also exists between the cation and anion, resulting in a two-dimensional network. In the cation, the carboxyl group is twisted with respect to the pyridine ring at a dihedral angle of 15.34†(17)°.