Tetraoxometalate [MO4](2-) bridges Cu(II) and Ni(II) ions to form dinuclear, trinuclear, and one-dimensional complexes. The crystal structures and magnetic properties of [{Cu(acpa)}(2)(mu-CrO4)]. 4CH(3)OH . 4H(2)O 1 and [{Cu(acpa>)}(2)(mu-MoO4)]. 4H(2)O 2, (Hacpa = N-(1-acetyl-2-propyridene)(2-pyridylmethyl)amine), catena-(mu-CrO4-O,O’[Ni(cyclam)]. 2H(2)O 3, [{Ni(cyclam)}(mu-MoO4)(2)-[H2O)(2)](ClO4)(2) 4, and [{Ni(cyclam)}(3)(mu-WO4)(2)(H2O)(2)](ClO4)(2) 5 were presented. Complexes 1 and 2 are isomorphous and the structures are made up of discrete dimers in which two copper(II) ions are bridged by the [MO4](2-) anion. In 3, Ni(II) ions are bridged by the chromate ion to form one dimensional chain, while in 4 and 5 two metalate ions bridge three Ni(II) ions to form trinuclear complexes. Magnetic susceptibility measurements for 1 and 3 revealed that ferromagnetic interactions between Cu(II) and Ni(II) ions are propagated through the [CrO4](2-) bridges and the coupling constants (J) were evaluated to be 7.3(1) cm(-1) (H = -2JS(1).S-2) for 1 and 0.6(1) cm(-1) for 3. In 2, 4, and 5, paramagnetic metal centers 1 are antiferromagnetically coupled with J values of -2.5(4), -1.7(1), -0.9(1) cm(-1) respectively. The ferromagnetic interactions in 1 and 3 are explained by means of the orbital topology of frontier orbitals.