The asymmetric unit of the title compound, C(10)H(6)N(2)·0.5C(4)H(4)O(4), consists of one quinoline-2-carbonitrile mol-ecule and a half-mol-ecule of fumaric acid, which lies on an inversion center. The quinoline-2-carbonitrile mol-ecule is almost planar, with an r.m.s. deviation of 0.008 (1) Å. The acid and base are linked together via pairs of inter-molecular C-H⋯O and O-H⋯N hydrogen bonds, forming R(2) (2)(8) ring motifs. In the crystal, the carbonitrile mol-ecules are further linked by inter-molecular C-H⋯N hydrogen bonds, generating R(2) (2)(10) ring motifs, resulting in zigzag chains running along the c axis.
* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.