The trans-oxamidato-bridged polymeric complexes [Cu₂(trans-oxen)(µ-OH)(µ-H₂O)]_nBr_n·2nH₂O 1 and [Cu₂(trans-oxen)(µ-OCN)₂]_n·nH₂O 2 [H₂oxen = N,N′-bis(2-aminoethyl)oxamide] with zig-zag co-ordination chains were synthesized and characterized by single-crystal X-ray diffraction methods. The cationic chains [{Cu₂(trans-oxen)(µ-OH)(µ-H₂O)}_n]ⁿ⁺ in 1 bridged alternately by trans-oxamidate, µ-OH and µ-H₂O arranged in three directions intersect with one another to yield an extended network via the interchain hydrogen bonds formed by metal-co-ordinated OH^– and H₂O and the solvate water molecules with the linkages Cu–OH· · ·OH–Cu and Cu–H₂O· · ·H₂O· · ·H₂O–Cu. The neutral chains [Cu₂(trans-oxen)(µ-OCN)₂]_n in 2 bridged alternately by trans-oxamidate and double cyanate bridges in an asymmetric N-bonded end-on mode are joined together by bridging H₂O molecules via the hydrogen bond linkage Cu(oxen)· · ·H₂O· · ·(oxen)Cu to produce the extended network structure. The magnetic calculations showed the presence of antiferromagnetic couplings between the copper(II) ions through both the trans-oxamidate and µ-OH or cyanate bridges.