In reactions of zirconocene dichloride, Cp2ZrCl2, with 1 equiv and an excess amount of LiBH3CH3, the methyltrihydroborate complexes, Cp2ZrCl{(mu-H)(2)BHCH3},1, and Cp2Zr{(mu-H)(2)BHCH3}(2), 2, were isolated. The reaction of titanocene dichloride, Cp2TiCl2, with an excess amount of LiBH3CH3 produced the monosubstituted methyltrihydroborate complex, CP2Ti{(mu-H)(2)BHCH3}, 3. The titanium was reduced from Ti(IV) to Ti(III), producing a 17-electron, paramagnetic titanocene complex. Under a dynamic vacuum at room temperature, compound 2 decomposed and produced the zirconium hydride compound Cp2ZrH{(mu-H)(2)BHCH3}. Single crystal X-ray structures of 1, 2, and 3 were determined. Crystal data for 1: space group P2(1)/c, a = 13.7921(3) Angstrom, b = 13.4227(3) Angstrom, c = 13.0868(3) Angstrom, beta = 91.6448(12)degrees, Z = 8. Crystal data for 2: space group Pna2(1), a = 15.2949(4) Angstrom, b = 9.3417(2) Angstrom, c = 9.3211(2) Angstrom, Z = 4. Crystal data for 3: space group Fmm2, a = 9.1795(3) Angstrom, b = 13.0993(5) Angstrom, c = 8.8520(3) Angstrom, Z = 4.