The title complex, [Cu4I4(C21H15N3)2], lies on an inversion centre located at the centroid of a four-membered ring formed by one of the crystallographically independent CuI ions and a triply bridging iodide ligand. The 2,2′:6′,2′′-terpyridine (phterpy) ligand chelates each of the independent CuI centres in a bidentate fashion, with the N atom of the central pyridyl ring bridging the two CuI centres and those of the outer pyridyl rings binding the two independent CuI ions individually to form a dinuclear system. These are further linked by triply-bridging I− anions to form the centrosymmetric tetra­nuclear units. One independent Cu atom binds to each of the inversion-related I− anions while the other coordinates to one bridging and one terminal monodentate iodide ligand. The outer pyridyl rings are twisted relative to the central pyridyl ring of the phterpy ligand with dihedral angles of 18.7 (1) and 35.6 (1)°, respectively.

The title compound, [CuI(C(11)H(10)N(2)S(2))](n), is built around centrosymmetric dinuclear Cu(2)I(2) cores, each of which is linked to four neighboring Cu(2)I(2) units via flexible dithioether ligands, viz. 4,4'-(methylenedithio)dipyridine, to form a two-dimensional grid containing rhombus-shaped cavities with diagonal distances of ca 15 and 22 A. Two of these networks interpenetrate in a woven fashion, and the resulting structure does not possess any open channels or cavities. Each Cu atom is in a distorted tetrahedral coordination environment.