Eight oxamato-bridged heterotrinuclear (NiCuNiII)-Cu-II-Ni-II complexes of formula {[Ni(H2O)(dPt)](2)(mu-Cu(H2O)(opba))}(ClO4)(2) (1), [Ni(H2O)(dien)](2)(mu-Cu(pba))}(ClO4)(2).6H(2)O (2), {[Ni(H2O)(MedPt)](2)(mu-Cu(OHpba))}(ClO4)(2).4H(2)O (3), {[Ni(H2O)-(dien)](2)(mu-Cu(Me(2)pba))}(ClO4)(2).2.5H(2)O (4), [Ni(H2O)(dPt)](2)(mu-Cu(Me(2)pba))}(ClO4)(2).2H(2)O (5), {[Ni(H2O)-(dien)](2)(mu-Cu(OHpba))}(ClO4)(2).4H(2)O (6), {[Ni-2(dPt)(2)(mu-Cu(H2O)(pba))](2)(mu-N-3)(2)}Na-2(ClO4)(4).6H(2)O (7), and [Cu(H2O)(2)(dpt)Ni-2-(H2O)(dpt)(2)](mu-H(2)Me(2)pba(2-))}(ClO4)(4).3H(2)O (8) in which opba = o-phenylenbis(oxamato), pba = 1,3-propylenebis(oxamato), OHpba = 2-hydroxy-1,3-propylenebis(oxamato), Me(2)pba = 2,2-dimethyl-1,3-propylenbis(oxamato), dpt = 3,3'-diaminodipropylamine, then = 2,2'-diaminodiethylamine, and Medpt = 3,3'-diamino-N-methyldipropylamine were synthesized and characterized. The crystal structures of 1, 7, and 8 were solved. For complex 1, the trinuclear entities are linked by hydrogen bonds forming a one-dimensional system, and for complex 8, the presence of van der Waals interactions gives a one-dimensional system, too. For complex 7, the trinuclear entities are self-assembled by azido ligands, given a hexanuclear system; each of these hexanuclear entities are self-assembled through two [Na(O)(3)(H2O)(3)] octahedral-sharing one-edge entities, given a one-dimensional system. The magnetic behavior of complexes 2-7 was investigated by variable-temperature magnetic susceptibility measurements. Complexes 2-6 exhibit the minimum characteristic of this kind of polymetallic species with an irregular spin state structure. The J value through the oxamato bridge varied between -88 cm(-1) (for 6) and -111.2 cm(-1) (for 5). For complex 7, the values obtained were J(1) = -101.7 cm(-1) (through the oxamato ligand) and J(2) = -3.2 cm(-1) (through the azido ligand).