The ligand 2,5-bis(4-hydroxy-2-thiabutyl)thiophene (L) and its polymeric complex (CuCl2 . L)(n) have been prepared. The complex (C10H16Cl2CuO2S3)(n) crystallizes in the orthorhombic system, space group P2(1)2(1)2(1), with a=6.8096(4) Angstrom, b=9.4542(5) Angstrom, c=22.899(3) Angstrom, Z=4. Each copper atom is six-coordinate with cis chlorines and trans sulfurs. One bond to chlorine and one to oxygen are elongated, and each copper is part of a zigzag (Cu-CI), chain. The chains are cross-linked by the organic ligand, which coordinates through each of its arms to different coppers by using thioether sulfur and hydroxyl oxygen. Electrical neutrality is achieved by the remaining chlorine required by stoichiometry being present as an isolated Cl- ion in empty spaces in the structure. The complex has been investigated by cyclic voltammetry, IR, and UV/vis spectroscopy, and the polymer structure has been observed to be destroyed upon dissolving. Magnetic susceptibility measurements (5-302 K) have been fitted to a uniform chain model with molecular field and paramagnetic ''impurity'' corrections. Intrachain (-2J=26.4 cm-L) and interchain (J'=-8.46 cm(-1)) couplings were found to be small and antiferromagnetic.