(a) Synthesis of free-base and transition metal derivatives. As a prelude to systematic studies of transition metal derivatives, we chose to optimize the literature synthesis of free-base 6azahemiporphycenes. The reported method consists of the interaction of a free-base mesotriarylcorrole with 4-aminotriazole in the presence of potassium hydroxide in refluxing toluene. In our hands, the protocol led to somewhat inconsistent yields. The reported involvement of isocorrole intermediates suggested an improved synthetic strategy. Following a recent synthesis of pyrrole-appended isocorroles in one of our laboratories, we attempted to generate the key isocorrole intermediate by oxidizing a free-base corrole with DDQ in dichloromethane at room temperature and trapping the resulting cation-radical with 4-aminotriazole. The new method indeed led to the desired 6-azahemiporphycene but in rather poor yields. Dissolving the 4aminotriazole in methanol, which we surmised might help, also proved unsatisfactory in that methanol was found to compete with 4-aminotriazole as a nucleophile, thus degrading the yield of the azahemiporphycene. Warming also did not confer any advantages, resulting simply in increased reversion of the corrole cation-radical to the neutral free base. It appeared that a polar solvent was needed, which would dissolve 4-aminotriazole but would not attack the corrole Transition metal AHP derivatives, M[X-AHP], were synthesized with three different para substituents X = H, Me and OMe and M = Pd, Pt and Mn (Chart 1). The metals inserted smoothly, with standard metal salts in hot or refluxing pyridine, as expected in light of the larger N4 core size of AHPs relative to corroles and isocorroles. Palladium insertion occurred fastest, reaching completion in ~3 h, while Mn and Pt insertion took ~16 h. The metal insertions could be conveniently followed visually, on account of marked changes in color of the reaction mixture, or with UV-vis-NIR absorption spectroscopy.