The compound, 5,10,15,20-tetrakis(4-methoxyphenyl)porphine zinc(II) (ZnTMPP), was prepared, and its thermochemical properties were experimentally established. The standard molar energy of combustion (triangle U-c degrees(m)) was determined from oxygen rotating-bomb combustion calorimetry experiments. The standard molar enthalpies of combustion (triangle H-c degrees(m)) and formation (triangle H-1 degrees(m)) were derived. The enthalpy of sublimation (triangle H-g(cr)degrees(m)) was determined by Knudsen effusion at high temperatures. With these results, the standard molar enthalpies of formation and atomization (triangle H-at degrees(m)) in the gas state were calculated. A summary of the results at T= 298.15 K (p degrees = 0.1 MPa) is shown in Table 1. Using these results and those previously obtained for the free ligand, 5,10,15,20-tetrakis(4methoxyphenyl)porphine, the mean dissociation enthalpy for the Zn-N coordination bond is obtained as D(Zn-N) = (160 +/- 9) kJ center dot mol(-1). This value is consistent with the results obtained using the same experimental approach in a similar system (5,10,15,20-tetraphenylporphine, TPP/ZnTPP) reported elsewhere. A discussion of the strength for the Zn-N coordination bond is made in terms of the structural and electronic features of the molecules involved.