The reaction of 1,4-dihydro-2,3-quinoxalinedione (H 2 L′) with CuCl 2 in the presence of LiOH in DMF has led to the 3D coordination polymer [Cu 3 L 2 Cl 2 (DMF) 4 ] n (1) with an (8 2 ·10)-a, lig (LiGe), topology, where L 2− is 2,3-dioxyquinoxalinate(−2). This compound is the first coordination polymer of any transition metal featuring L 2− and contains the ligand in a novel 3.1111 (Harris notation) coordination mode. IR data are discussed in terms of the chemical composition of the polymer and the coordination mode of L 2− . Variable-temperature (2–300K) magnetic susceptibility and variable-field (0–5T) magnetization studies reveal that L 2− propagates weak antiferromagnetic exchange interactions through its “quinoxaline” moiety.