In reactions of Cp2ZrCl{(mu-H)(2)BC5H10}, 1, with LiH, Cl- is replaced to produce Cp2ZrH{(mu-H)(2)BC5H10}, 2. Reaction of 1 with K[H2BC5K10] yields Cp2Zr{(mu-H)(2)BC5H10}(2), 4 The methyl-substituted compound Cp2Zr(CH3){(mu-H)(2)BC5H10}, 3, is prepared from the reaction of Cp2ZrCl(CH3) with K[H2BC5H10]. The synthetic route for the preparation of 3 prevents side reactions that occur in the direct alkylation of zirconocene organohydroborate complexes. Proton NMR spectra of 2 at elevated temperatures indicate that intramolecular hydrogen exchange occurs among Zr-H-B hydrogens, terminal H on Zr, and Cp hydrogens. The structures of 2, 3, and 4 are reported. Crystal data for 2 : space group Abm2 (No. 39), a = 11.423(2) Angstrom, b = 14.138(3) Angstrom, c = 9.025(5) Angstrom, Z = 4. Crystal data for 3 : space group Pbca (No. 61), a = 8.469(4) Angstrom, b = 16.828(9) Angstrom, c = 21.897(8) Angstrom, Z = 8. Crystal data for 4 : space group C2/c (No. 15), a = 16.222(7) Angstrom, b = 9.434(2) Angstrom, c = 13.131(5) Angstrom, beta = 102.97(3)degrees, Z = 4.