Two new ligands, 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenoI (HL) and 2-[(bis(2-pyridylmethyl)amino)methyl]-4- methyl-6-(methylthio) phenol (HSL), were synthesized and were used to prepare the trinuclear copper(II) complex {[CuSL(Cl)](2)Cu}(PF6)(2)center dot H2O (1) and the corresponding binuclear complexes [Cu-2(SL)(2)](PF6)(2) (2) and [Cu2L2](PF6)(2) (3). The crystal structure of 1 shows two different coordination environments: two square base pyramidal centers (Cu1 and Cu1a, related by a C-2 axes), acting as ligands of a distorted square planar copper center (Cu2) by means of the sulfur atom of the SCH3 substituent and the bridging phenoxo oxygen atom of the ligand (Cu-2-S = 2.294 angstrom). Compounds 2 and 3 show two equivalent distorted square base pyramidal copper(II) centers, bridged in an axial-equatorial fashion by two phenoxo groups, thus defining an asymmetric Cu2O2 core. A long copper-sulfur distance measured in 2 (2.9261(18) angstrom) suggests a weak bonding interaction. This interaction induces a torsion angle between the methylthic, group and the phenoxo plane resulting in a dihedral angle of 41.4(5)degrees. A still larger distortion is observed in 1 with a dihedral angle of 74.0(6)degrees. DFT calculations for 1 gave a ferromagnetic exchange between first neighbors interaction, the calculated J value for this interaction being +11.7 cm(-1). In addition, an antiferromagnetic exchange for 1 was obtained for the second neighbor interaction with a J value of -0.05 cm(-1). The Bleaney-Bowers equation was used to fit the experimental magnetic susceptibility data for 2 and 3; the best fit was obtained with J values of +3.4 and -16.7 cm(-1), respectively. DFT calculations for 2 and 3 confirm the nature and the values of the J constants obtained by the fit of the experimental data. ESR and magnetic studies on the reported compounds show a weak exchange interaction between the copper(II) centers. The low values obtained for the coupling constants can be explained in terms of a poor overlap between the magnetic orbitals, due to the axial-equatorial phenoxo bridging mode observed in these complexes.