4,4'-Bipyridyl N,N'-dioxide-3-hydroxy-2-naphthoic acid (1/2).

4,4'-Bipyridyl N,N'-dioxide crystallizes with 3-hydroxy-2-naphthoic acid to give a centrosymmetric three-component adduct, C(10)H(8)N(2)O(2).2C(11)H(8)O(3), which is engineered into a two-dimensional layer structure by two kinds of pi-pi interactions. Weak C-H...O interactions further link the two-dimensional structure into a three-dimensional structure.