Bis(1,1-diphenylhydrazido(1-))ruthenium(IV) porphyrins. [Ru-IV(Por)(NHNPh2)(2)] (Por = TPP, TTP, 4-Cl-TPP, 4-MeO-TPP), were prepared in similar to 60% yields through the reaction of dioxoruthenium(VI) porphyrins, [Ru-IV(Por)O-2], with 1,1-diphenylhydrazine in ethanol. This new type of ruthenium complex has been characterized by H-1 NMR, IR, UV-vis, and FABMS with elemental analysis. The crystal structure of [Ru-IV(TTP)(NHNPh2)(2)], which reveals an eta(1)-coordination mode for both hydrazido axial ligands, has been determined. The average Ru-NHNPh2 distance and Ru-N-N angle were found to be 1.911(3) Angstrom and 141.1(3)degrees, respectively. The polphyrin ring exhibits a ruffling distortion that is unprecedentedly large for ruthenium complexes with simple porphyrinato ligands (such as TTP). This is probably due to the steric effect of the axial hydrazido(1-) ligands.