Schiff base chelating ligands are known to form a large family of metal complexes with some of them having been found to behave as molecular magnets. In this work we report the synthesis of two novel copper(II) dimers (I) of N, O, O- or N, O, S - tridentate Schiff bases derivatives of 3-allylsalicylic aldehide and o-aminophenole or aminothiophenole.fgiureThe binuclear structure of I was established by EXAFS spectroscopy data collected at the Station К1.3b "Structural Materials Science" of the Kurchatov Center of Synchrotron Radiation and Nanotechnology. The magnitudes of Fourier transforms (MFT) of k3 -weighted experimental and simulated EXAFS data of the Cu K-edges for complexes and copper(II) acetate as standard are depicted on Fig.1. Analysis of MFT revealed the binuclear structure for both I(a,b) compounds, where the Cu….Cu bond occurs through the oxygen for Ia or sulfur bridges for Ib. The quantitative parameters for nearest coordination spheres in I(a,b) were obtained as a result of non linear multi-sphere approximation of simulated EXAFS spectra to the experimental results. In Ia the distances Cu…Cu и Cu…O are R = 3.020.02 Å and R = 1.940.02 Å. In Ib the distances Cu…Cu и Cu…S are R = 2.960.02 Å and R = 2.280.02 Å, correspondingly.fgiureFig. 1. MFT of k3 -weighted EXAFS CuK-edges for 1-copper acetate, 2-complex 1a, 3- complex Ib. Magnetic susceptibility measurements in the temperature range 300-2 K (Fig. 2) confirm the dimeric structure for both complexes and revealed very strong antiferromagnetic exchange (2J for Ia -365 cm-1, and -950cm-1 for Ib).figureFig. 2. Plot of χmT vs T and µeff vs T for complex