The synthesis of the highly encapsulating pyrazolylborate ligand hydrotris(3-p-cumenyl-5-methylpyrazolyl)borate (L = Tp^Cum,Me) and of its zinc hydroxide complex L·Zn−OH (1) are described. 1 is converted by H₂S into the hydrosulfide complex L·Zn−SH (2). Both 1 and 2 seem to be contaminated with traces of the isomeric species 1‘ and 2‘ containing L‘ with one 3-methyl-5-p-cumenyl substituent. Thermal condensations of 1‘ and 2 yield the molecular zinc oxide and sulfide complexes L‘·Zn−O−Zn·L‘ (3‘) and L·Zn−S−Zn·L (4). The hydroxide complex 1 has been found to react readily with cumulated double-bonded species:  CO₂ is incorporated in alcoholic solutions to form the alkylcarbonate complexes L·Zn−OCOOR (5). Similarly, CS₂ in ethanol forms the O-ethyl dithiocarbonate complex L·Zn−SC(S)OEt (6). SO₂ is converted to a bridging sulfito ligand in L·Zn−O-SO−O−Zn·L (7), and phenyl isothiocyanate is bound as a thiocarbamidato ligand in L·Zn−SC(O)NHPh (8). Complexes 1, 2, 2‘, 3‘, 4, 5, and 6 have been confirmed by structure determinations and complexes 7 and 8 by spectral data.