Poly[[[μ-trans-1,2-bis-(pyridin-4-yl)ethene-κ(2) N:N']-μ-iodido-copper(I)]-trans-1,2-bis-(pyridin-4-yl)ethene (1/0.25)].

The title compound, {[CuI(bpe)]·0.25(bpe)} (n) , was synthesized similarly to (CuI)(2)(bpe) [Neal et al. (2019 ▸). IUCrData, 4, x190122] with red crystals grown from aceto-nitrile solutions of CuI and the bpe ligand [bpe = 1,2-bis-(pyridin-4-yl)ethene, C(12)H(10)N(2)]. The structure of the title compound is a type 1 complex in the Graham nomenclature [Graham et al. (2000 ▸). Inorg. Chem. 39, 5121-5132], having rhombic dimers of Cu(2)I(2) that are bridged by two bpe ligands, to form oligomeric ribbons arranged as stairsteps. The step height is 2.8072†(11)†à , which is the Cu-I(i) distance of the dimer [symmetry code (i): 1 - x, 2 - y, 1 - z]. The resulting polymer displays a two-dimensional honeycomb framework along the (01) plane, and disordered free bpe mol-ecules fill the voids in the crystal.