The influence of fluorinated substituents on the luminescent properties of rhenium-oxo, osmium-nitrido and gold triarylcorroles was studied via a comparison of four ligands: triphenylcorrole (TPC), tris(p-trifluoromethylphenyl)corrole (TpCF3PC), tris{3,5bis(trifluoromethyl)}corrole (T3,5-CF3PC), and tris(pentafluorophenyl)corrole (TPFPC). The majority of the compounds have been previously synthesized; All the complexes proved emissive in deoxygenated toluene at room temperature (Figure ). The emission was efficiently quenched by molecular oxygen and is thus ascribed to phosphorescence. The absorption and excitation spectra (Figures ) proved virtually identical, indicating that the emission originates solely from the metal complexes, while also confirming the purity of the compounds. Although the emission spectra of the T3,5-CF3PC and TPFPC complexes are generally similar to those of the previously studied TPC and TpCF3PC complexes (Figure and Table ), the emission maxima were found to shift hypsochromically with increasing electron-withdrawing character of the meso-aryl substituents; this effect is observed for all three metal series examined. As shown in Table , fluorination results in an increase in both luminescence quantum yields and decay times in the order TPC < TpCF3PC < T3,5-CF3PC < TPFPC, which is also the order of the redox potentials. Figure emits as efficiently as Os[TPC](N). The trend in the luminescence decay times parallels that observed for the luminescence quantum yields (Table ). The decay time of Au[TPFPC] is thus much longer (170 µs) than that for the other Au triarylcorroles (94-99 µs). The fact that the order of phosphorescence quantum yields parallels the order of redox potentials for each of three series of 5d metallocorroles (Table ) suggests that the mechanism of enhanced luminescence is largely electronic in origin. However, the ortho fluorines in the TPFPC complexes may confer some degree of conformational rigidity, leading to increased triplet lifetimes. Fluorination also has a major impact on solute-solvent interactions, which in turn may also affect the luminescence properties. At this point, these potential influences remain to be disentangled and the striking impact of fluorination has been presented only as an empirical observation.