The thermal behaviour of some nitrogen-ligated complexes of 2-Guanidmobenzimi­dazole (GBM), 1,2 dimorpholinoethane (DME), 1,3 dimorpholinopropane (DMP) with Co(II) have been studied by thermogravimetry and differential thermal analysis. Complete decomposition of the chelates, obtained from the above Iigands, was accomplished generally in two stages. All DMP comp­lexes studied in the prellent investigations were found to be thermally less stable than the corresponding DME complexes. While most of the GBM and DME complexes were obllerved to be of comparable sta­bility. The differential thermal analysis of Co(ll) complexes are also reported. The reaction found in DTA curves corresponded to those found in the TGA curves.