The crystal solvates of complexes MP (P is the dianion of tetrakis(3,5-di-t-butylphenyl)porphin, M=Ni(II), Zn(II)) and (Ac)MnP with pyridine have been obtained by isothermal evaporation of corresponding solutions at 35°C. The formation and the decomposition temperatures of crystal solvates and enthalpies of evaporation pyridine molecules from those crystal solvates were received using thermogravimetric method. In addition to that, an influence of the type of metal on the compositions, the energetic and thermal stabilities of the received complexes were analyzed.