Two new polynuclear complexes [Ni-6(amox)(6)(mu(6)-O)(mu(3)-OH)(2)]Cl-2-6H(2)O and [Cu-3(amox)(3)(mu(3)-OH)(mu(3)-Cl)]ClO4.4H(2)O (amox(-) = anion of 4-amino-4-methyl-2-pentanone oxime) have been synthesized and characterized structurally and magnetically. The Ni(II) complex contains a novel Chinese-lantern-like Ni-6 cage centered by an oxo ion. It contains the nearest octahedral Ni(II)...Ni(II) separation (<2.8 Angstrom) and exhibits strong antiferromagnetic properties. The Cu(II) complex has a cyclic trinuclear copper(II) core bridged by both mu(3)-OH- and mu(3)-Cl- ions. The magnetic susceptibilities of both antiferromagnetic complexes were fitted by using approximate models.