New polyborate salts containing bulky non-metal cations have been prepared from either the free organic base or the [non-metal cation][OH] in methanolic aqueous solution: 1-adamantylammonium pentaborate [C10H18N][B5O6(OH)4] (1), 2-adamantylammonium pentaborate dihydrate [C10H18N][B5O6(OH)4].2H2O (2), N,N-dimethyl-1-adamantylammonium pentaborate.boric acid monohydrate [C12H22N][B5O6(OH)4].B(OH)3.H2O (3), N,N,N-trimethyl-1-adamantylammonium pentaborate trihydrate [C13H24N][B5O6(OH)4].3H2O (4), N,N,N-trimethyl-2-adamantylammonium pentaborate trihydrate [C13H24N][B5O6(OH)4].3H2O (5), dibenzylammonium pentaborate sesquihydrate [C14H16N][B5O6(OH)4].1.5H2O (6), bis(triphenylphosphine)iminium pentaborate sesquihydrate [C36H30NP2][B5O6(OH)4].1.5H2O (7), bis(triphenylphosphine)iminium triborate.2.5 hydrate [C36H30NP2][B3O3(OH)4].2.5H2O (8), 4,4’-bipiperidinium heptaborate dihydrate [C10H22N2][B7O9(OH)5].2H2O (9). All compounds were characterized by thermal (TGA/DSC), and spectroscopic analysis (NMR, IR). Compounds 3 - 5 and 9 have been characterized by single-crystal XRD studies. The waters of crystallization in 3 - 6 and the boric acid of crystallization in 3 play important structural roles in expanding the supramolecular pentaborate(1-) lattices to accommodate the bulkier cations.