AbstractThe zinc hydroxide complexes Tp*Zn–OH with TpCum,Me = tris(3‐cumenyl‐5‐methylpyrazolyl)borate and TptBu,Me = tris(3‐tert‐butyl‐5‐methylpyrazolyl)borate can be converted to the alkyl carbonate complexes Tp*Zn–OCOOR by reaction with dialkyl dicarbonates or with alcohol and CO2. An alternative formation reaction is the treatment of the pyrazolyl borate with zinc perchlorate and potassium carbonate in alcohol. The interconversion between TpCum,MeZn–OH and TpCum,MeZn–OCOOMe in methanol‐containing solution can be repeatedly performed in both directions by bubbling either CO2 or N2 through the solution. The alkyl carbonate complexes show a variable sensitivity towards hydrolytic destruction with reformation of the hydroxide complexes. The complexes TptBu,MeZn–OCOOR (R = Me, Et) release CO2 under high vacuum to form the alkoxide complexes TptBu,Me‐Zn–OR, which could not be obtained pure due to their extreme water sensitivity. Indirect evidence for their existence is also obtained by the reaction between TpCum,MeZn–OCOOMe and methyl iodide, forming TpCum,MeZn–I and dimethyl ether. The Zinc hydroxide complexes catalyse the formation of diethyl carbonate from ethanol and CO2.