Thermogravimetry, derivative thermogravimetry and infrared spectra have been applied to the investigation of the thermal behaviour and spectral properties of the dimeric complexes Cu 2 (2-Clbz) 4 (denia) 2 (I), Cu 2 (2-Brbz) 4 (denia) 2 (II) and Cu 2 (3-Brbz) 4 (denia) 2 (III), where 2-Clbz, 2-Brbz and 3-Brbz = 2-chloro, 2-bromo-and 3-bromobenzoate anions, denia = N,N-diethylenicotinamide. Thermal decompositions of all studied compounds proceed in two steps. The final product of thermal decomposition is CuO. The thermal stability of the complexes can be ordered in the sequence I \ II \ III.