New azo compounds containing barbituric acid, thiobarbituric acid or thiouracil, together with their complexes, were prepared. All the complexes are tetrahedral. Axial ESR spectra were observed for the complexes with a d x2Ày2 ground state with small g || values indicating strong interaction between the ligands and their metal ions. Conductivity measurements proved semiconducting properties for the ligands and their complexes. Energies of activation (ÁE a) and order of the thermal reactions (n) were calculated by DTA.