A series of complexes of copper(I) halides with either [12]aneS₄ (1,4,7,10-tetrathiacyclododecane) or [16]aneS₄ (1,5,9,13-tetrathiacyclohexadecane) have been synthesized, characterised and their crystal structures determined. Discrete molecular entities of formula [CuX([12]aneS₄)] (X = Cl, Br or I) were isolated from solutions containing a 1∶1 metal∶ligand stoichiometry. In [CuX([12]aneS₄)] (X = Br or I) the copper(I) centres adopt a rare square pyramidal geometry. Located on fourfold axes of symmetry, the copper(I) centres are co-ordinated by one halide ion [Cu–Br 2.4209(11) or Cu–I 2.573(5) Å] and four sulfur atoms [2.5386(12) (X = Br) and 2.521(5) Å (X = I)]. In contrast, the copper(I) centres in [CuCl([12]aneS₄)] adopt the more common tetrahedral co-ordination geometry, which is provided by one chloride ion [Cu–Cl 2.2666(13) Å] and three sulfur donors [Cu–S 2.3331(13), 2.3326(13), 2.4720(11) Å]. Polymeric materials, [Cu₄Br₄([12]aneS₄)₂]_∞, [Cu₄I₄([12]aneS₄)]_∞ and [Cu₂I₂([16]aneS₄)]_∞, were obtained from reactions in which metal∶ ligand stoichiometries of 2∶1 and 4∶1 were used. [Cu₄Br₄([12]aneS₄)₂]_∞ contains a previously uncharacterised copper(I) halide motif of formula Cu₄X₄ which is derived from the common Cu₄X₄ cubane tetramer and the Cu₄X₄ step-cubane tetramer. These Cu₄X₄ clusters are linked by [12]aneS₄ molecules to generate a two-dimensional framework [Cu–Br 2.410(2)–2.539(2); Cu–S 2.318(3)–2.385(3) Å]. In [Cu₄I₄([12]aneS₄)]_∞, Cu₄I₄ cubane tetramers are linked by tetradentate [12]aneS₄ molecules to give a two-dimensional sheet structure [Cu–I 2.602(1)–3.021(1); Cu–S 2.285(1)]. In [Cu₂I₂([16]aneS₄)]_∞ an infinite three-dimensional co-ordination polymer comprising Cu₂I₂ rhomboid dimers linked by tetradentate [16]aneS₄ molecules is formed [Cu–I 2.5972(9)–2.6702(9); Cu–S 2.292(2)–2.357(2) Å]. The Cu₂I₂ moiety acts as a pseudo-square planar linker while the bridging [16]aneS₄ units afford tetrahedral building blocks to give overall a PtS type structure for the polymer.