Since its introduction in 2010 by Suginome et al., pinB-Bdan [pin = OCMe 2 CMe 2 O, dan = (NH) 2 (C 10 H 6 )] has become a valuable reagent in various regioselective (bis-)borylation reactions, and related unsymmetrical diborane(4) derivatives have been used as versatile precursors for diaminoboryl complexes. However, the unsymmetrical diborane(4) derivatives employed show little variation of the diol and diamine moieties. The present study expands this class of compounds and reports the synthesis of unsymmetrical diborane(4) derivatives