NMR spectroscopy is demonstrated to be a powerful analytical tool for the study of solvolysis and ligand-exchange chemistry of the [Zr6BCl12](+) cluster in acetonitrile, methanol, and pyridine. B-11 NMR spectra for [(Zr6BCl12)Cl6-xLx](x-5) (L = CH3CN, CH3OH, and pyridine; x = 1-6) are reported. Exceedingly narrow B-11 lines are generally observed for these clusters. Two-bond ((2)J(P-Zr-B) = 8.8 Hz) and three-bond coupling constants ((3)J(P-O-Zr-B) = 1.9 HZ) are observed for the cluster complexes [(Zr6BCl12)(PR3)(6)](+) and [(Zr6BCl12)(OPR3)(x)L6-x](+) (L = CH3CN and PR3), respectively, in both B-11 and P-31 NMR spectra. Spin-lattice relaxation times (T-1＇s) for B-11 were measured for several cluster complexes.. Homoleptic species; [(Zr-BCl12)L-6](+) (L = CH3CN, CH3OH, pyridine), exhibit very long times and that for [(Zr6BCl12)(NCCH3)(6)](+) is the longest ever measured (T-1 = 108 s) for the B-11 nucleus. A thermodynamic analysis of spectra for the [(Zr6BCl12) (CH3OH)(6-x)(py)(x)](+) (x = 0-5) System reveals that [Zr6BCl12](+) binds pyridine more strongly than methanol by about 3 kJ/mol. Crystallographic structural analyses of [(Zr6BCl12)Cl(py)(5)]. 3CH(3)CN and [pyH]-{cis-[(Zr6BCl12)Cl-2(py)(4)]}. 3py are also reported. The following parameters were determined for these two compounds : [(Zr6BCl12)Cl(py)(5)]. 3CH(3)CN, orthorhombic, Pbcm, a 13.4268(1) Angstrom, b = 25.8258(1) Angstrom, c 14.5918(2) Angstrom, Z = 4; [pyH]{cis-[(Zr6BCl12)Cl-2(py)(4)]}. 3py, monoclinic, C2/c, a = 14.5999(3) Angstrom, b = 21.2298- (5) Angstrom, c 19.8292(5) Angstrom, beta = 101.892(1)degrees, Z = 4.