The trinudear [Cu-3(RCOO)(4)(H(2)TEA)(2)] copper(II) complexes, where RCOO- = 2-furoate (1), 2-methoxybenzoate (2), and 3-methoxybenzoate (3, 4), as well as dimeric species [Cu-2(H(2)TEA)(2)(RCOO)(2)]center dot 2H(2)O, have been prepared by adding triethanolamine (H(3)TEA) at ambient conditions to hydrated Cu(RCOO)(2) salts. The newly synthesized complexes have been characterized by elemental analyses, spectroscopic techniques (IR and UV-visible), magnetic susceptibility, single crystal X-ray structure determination and theoretical calculations) using a Difference Dedicated. Configuration Interaction approach for the evaluation of magnetic coupling constants. In 1 and 2, the central: copper atom lies on an inversion center, while in the polyrnorphs 3 and 4, the three metal centers are crystallographically independent. The zero-field splitting parameters of the trimeric compounds, D and E, were derived from high-field, high-frequency electron paramagnetic resonance spectra at temperatures ranging froni 3 to 290 K and were used for the interpretation of the magnetic data. It was found that the dominant intefaction between the terminal and central Cu sites J(23) is ferromagnetic in nature in all complexes, even though differences have been found between the symmetrical or quasi-symmetrical complexes 1-3 and non-syrnnietrical complex 4, while the interaction between the terminal centers, J(23), is negligible.