The anionic dihydride complex [Cp2TaH2](-) was synthesized as a well-defined molecular species by deprotonation of Cp2TaH3 while different solubilizing agents, such as [2.2.2]cryptand and 18-crown-6, were applied to encapsulate the alkali-metal counterion. The ion pairs were characterized by multiple spectroscopic methods as well as X-ray crystallography, revealing varying degrees of interaction between the hydride ligands of the anion and the respective countercation in solution and in the solid state. The [Cp2TaH2](-) complex anion shows slow exchange of the hydride ligands when kept under a D-2 atmosphere, but a very fast reaction is observed when [Cp2TaH2](-) is reacted with CO2, from which Cp2TaH(CO) is obtained as the tantalum-containing reaction product, along with inorganic salts. Furthermore, [Cp2TaH2](-) can act as a synthon in heterobimetallic coupling reactions with transition-metal halide complexes. Thus, the heterobimetallic complexes Cp2Ta(mu-H)(2)Rh(dippp) and Cp2Ta(mu-H)(2)Ru(H)(CO)((PPr3)-Pr-i)(2) were synthesized and characterized by various spectroscopies and via single-crystal X-ray diffraction. The new hydride bridged tantalumrhodium heterobimetallic complex is cleaved under a CO atmosphere to yield mononuclear species and slowly exchanges protons and hydride ligands when exposed to D-2 gas.