'Given the many-applications of ruthenium porphyrins, the rarity of ruthenium corroles and the underdeveloped state of their chemistry;are clearly indicative of an area ripe for significant breakthroughs. The tendency of ruthenium corroles to form unreactive metal-rnetal-bonded dimers has been recognized as a key impediment in this area. Herein, by exposing, free-base meso-tris(p-X-phenyl)corroles, H-3[TpXPC] (X = CF3, H, Me and OMe), and [Ru(COD)Cl-2](x), in refluxing 2-methoXyethanol to nitrate, we have been able to reliably intercept the series Ru[TpXPC](NO) in a matter :of seconds to minutes and subseqnently Ru-VI[TpXPC](N), the products of a second deoxygenation, over some 16 h. Two of the (RuN)-N-VI complexes and one ruthenium corrole dimer could be crystaltographically analyzed; the Ru-N-nitrido distance was found to be similar to 1.61 angstrom, consistent with the triple-bonded Charecter of the (RuN)-N-VI units and essentially identical with the Os-N-nitrido distance, in analogous osmium correles Spectrostopic and, density functional theory (DFT) calculations suggest hat the RuNO corroles are best viewed as innocent {RuNO}(6) complexes, whereas the analogous FeNO corroles are noninnocent, i.e, best viewed as {FeNO}(7)-corrole(center dot 2-). Both (RuN)-N-VI and (OsN)-N-VI corroles exhibit sharp Soret bands, suggestive, of an innocent inacrocycle. A key difference between the two rnetals is that the Sotet maxima of the (OsN)-N-VI corroles are red-shifted some 25 non relative to those of the (RuN)-N-VI complexes. Carefal time-dependent DFT studies indicate that this difference is largely. attributable to relativistic effects in (OsN)-N-VI corroles. The availability, of two new classes Of mononuclear ruthenium corroles potentially opens the door to new application's, in such areas as catalysis and cancer therapy.