4-[(E)-2-(Pyridin-2-yl)ethen-yl]pyridine-terephthalic acid (2/1).

The title 2:1 co-crystal, 2C12H10N2·C8H6O4, crystallizes with one mol-ecule of 4-[(E)-2-(pyridin-2-yl)ethen-yl]pyridine (A) and one half-mol-ecule of terephthalic acid (B) in the asymmetric unit. In the crystal, the components are linked through heterodimeric COOH⋯Npyridine synthons, forming linear aggregates of composition -A-B-A-B-. Further linkage through weak C-H⋯O and C-H⋯π inter-actions gives two-dimensional hydrogen-bonded undulating sheets propagating in the [100] and [010] directions. These layers are connected through additional weak C-H⋯O contacts, forming a three-dimensional structure.