Through two different techniques TGA and DSC the thermal decomposition processes of salicyaldehyde G-P complexes having the general formula: $$[MCl_2(L)_2]^{2+}$2Cl^-$</TEX>; where L = salicyaldehyde carbohydrazone pyridinum cation, and M= Fe(III), Co(II), Cu(II) and Zn(II), have been studied. From the obtained thermogravimetric curves the following parameters n, $E_{alpha}$, A, ${Delta}S^{ eq}$, ${Delta}H^{ eq}$ and ${Delta}G^{ eq}$ were evaluated. The effect of the nature of the metal ions present in the complexes studied upon the calculated thermodynamic parameters was reported. A suitable mechanism for the thermal decomposition process was suggested.