New complexes of the type [{M x M′1−x (dadb)} n ·yH2O] {where dadbH2 =2,5-diamino-3,6-dichloro-1,4-benzoquinone (1); M=Cu(II); M′=Zn(II); x =1 (2), 0.5 (4), 0.0625 (5), 0 (3); y =0–2 and n =degree of polymerization} were synthesized and characterized. Distinct identities of heterobimetallic complexes are revealed from nature and position of their PXRD lines. Complexes under present study are hygroscopic in the temperature range RT–60°C. The TGA, DTA and DSC thermograms suggest that complexes first lose water molecules followed by loss of HCl molecules under 2nd step of thermal degradation which is catalyzed by Cu(II) ions, whereas elimination of CO under 3rd step is catalyzed by air. Residue from 2 and 3 corresponds to 1/2 mole of metallic copper and zinc, respectively, under nitrogen atmosphere, whereas, one mole of CuO and half mole of ZnO, respectively under air. Thermal degradation pattern of the ligand moiety around Cu(II) have been observed to be different than that around Zn(II) ion.