[en] Reaction of oxo-bis(tetrachlorocatecholate) Tc(V) complex [(n-C₄H₉)₄N][TcO(C₆Cl₄O₂)₂] (1) with n, N-diphenylhydrazine in Ch₂Cl₂ yields the binuclear paramagnetic Tc(V)/Tc(VI) mixed-valence complex [(n-C₄H₉)₄N][Tc₂(NNPh₂)₂(C₆Cl₄O₂)₄]xCH₂Cl₂x2CH₃OH (2). The structure of the molecular anion of 2 consists of two distorted octahedral Tc centers bridged by two hydrazido (2-) groups bonding s in the η¹ mode, an unusual bonding motif for this ligand, having previously described only for cyclopentadienyl-metal species. Complex 2 is also a unique example of a Tc(V)/Tc(VI) mixed-valence species; the Tc-Tc distance of 2.612 (2) angstrom is consistent with direct metal-metal interaction. Crystal data for 1 and 2. 46 refs., 2 figs., 5 tabs