The cocrystal of 3-hydroxy-2-naphthoic acid and 4,4'-bipyridine.

4,4'-Bipyridine cocrystallizes with 3-hydroxy-2-naphthoic acid in a 1:2 ratio to give a centrosymmetric three-component supramolecular adduct, namely 3-hydroxy-2-naphthoic acid-4,4'-bipyridine (2/1), C11H8O3.0.5C10H8N2, in which 4,4'-bipyridine is located on an inversion center. The pyridine-carboxylic acid heterosynthon generates an infinite one-dimensional hydrogen-bonded chain via pi-pi interactions between naphthyl and 4,4'-bipyridine groups. The one-dimensional chains are further assembled into a three-dimensional network by weak C-H...pi interactions between pyridyl and naphthyl rings, and C-H...O interactions between 3-hydroxy-2-naphthoic acid molecules.