title: 4,4'-(Ethene-1,2-diyl)dipyridinium bis-[4-(2-carboxy-benzo-yl)benzoate].
abstract: In the crystal structure of the title compound, C(12)H(12)N(2) (2+)·2C(15)H(9)O(5) (-), the cation has site symmetry with the mid-point of C=C bond located on an inversion center. The two benzene rings of the anion are oriented at a dihedral angle 85.87 (6)°. In the crystal, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds link the cations and anions into supra-molecular double chains, which are further connected into a three-dimensional network through inter-molecular C-H⋯O and π-π stacking between parallel pyridine rings [centroid-centroid distance = 3.4413 (12)Å] and between parallel benzene rings [centroid-centroid distance = 3.6116 (14)Å].
authors.forename: Cai
authors.initials: C
authors.lastname: Li
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.forename: Xue-Gang
authors.initials: XG
authors.lastname: Zheng
authors.forename: Xi-Jun
authors.initials: XJ
authors.lastname: Ke