title: 4,4'-Bipyrid-yl-4,4'-(hy-droxy-methyl-ene)dibenzoic acid (1/1).
abstract: In the title 1:1 co-crystal, C(10)H(8)N(2)·C(15)H(12)O(5), strong inter-molecular O-H⋯N hydrogen bonds link alternating mol-ecules of 4,4'-(hy-droxy-methyl-ene)dibenzoic acid and 4,4'-bipyridyl into zigzag chains in [501]. The crystal packing also exhibits π-π inter-actions between the 4,4'-bipyridyl rings of neighbouring chains [centroid-centroid distance = 3.608 (3) Å] and weak C-H⋯O hydrogen bonds.
authors.affiliation: Faculty of Materials Science & Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211,  People's Republic of China.
authors.forename: Lan
authors.initials: L
authors.lastname: Qin
authors.forename: Lan-Ping
authors.initials: LP
authors.lastname: Xu
authors.forename: Lei
authors.initials: L
authors.lastname: Han