The title compound, C10H5FN2, is a monoclinic (P21/c) polymorph of the previously reported triclinic (P-1) form [Anti-pin et al. (2003 ▶). J. Mol. Struct. 650, 1-20]. The 13 non-H atoms in the title polymorph are almost coplanar (r.m.s. deviation = 0.020 Å); a small twist between the fluoro-benzene and dinitrile groups [C-C-C-C torsion angle = 175.49 (16)°] is evident in the triclinic polymorph. In the crystal, C-H⋯N inter-actions lead to supra-molecular layers parallel to (-101); these are connected by C-F⋯π inter-actions.