substituted benzenediazonium tetraphenylborates to form 1,2,4,3λ4-triazaborines or 1,3,2λ4-oxazaborines. The formation of either the first or the second product is affected by the reaction conditions, especially by the presence of water in the reaction components and in the solvent. If the reaction is performed under anhydrous conditions, the major product is the triazaborine. When ‘wet’ diazoniumsalts are