The compounds Co(AcAc)(2)nL, where AcAc represents acetylacetonate, L the piperazine (Pipz), morpholine (Morph), piperidine (Pipd), pyridine (Py), 3-methylpyridine (beta-Pico), 4-methylpyridine (gamma-Pico), 3-cyanopyridine (3-cyanopy), 4-cyanopyridine (4-cyanopy), 2,2'-bipyridine (Bipy) or quinoline (Quin); n = 1 or 2) were synthesized and characterized by melting points, elemental analysis, thermal studies and electronic and IR spectroscopy. The enthalpies of dissolution in 10% (v/v) ethanolamine in methanol, 10% (v/v) triethanolamine in azeotropic methanol-dichlorethane mixture, 10% (v/v) diethanolamine in azeotropic methanol-dichlorethane mixture or 25% (v/v) aqueous HCl 1,2 N in methanol were measured. Appropriate thermochemical cycles then give the standard enthalpy change for the Lewis acid/base reaction (Delta(f)H(theta)), the standard enthalpies of formation (Delta(f)H(theta)), the standard enthalpies of decomposition (Delta(D)H(theta), the standard lattice enthalpies (Delta(M)H(theta)) and the standard enthalpies of the Lewis acid/base reactions in the gaseous phase (Delta(f)H(theta)(g)). The mean standard enthalpies of the cobalt-nitrogen bonds have been estimated.