Polar and apolar boron-based triple bonds promote the single and double C–H activation of acetone following similar coordination-deprotonation mechanisms.

Reduction of (CAAC)BBr2(NCS) (CAAC=cyclic alkyl(amino)carbene) in the presence of a Lewis base L yields tricoordinate (CAAC)LB(NCS) borylenes which undergo reversible E/Z‐isomerization. The same reduction in the absence of L yields deep blue, bis(CAAC)‐stabilized, boron‐doped, aromatic thiazolothiazoles resulting from the dimerization of dicoordinate (CAAC)B(NCS) borylene intermediates.

The reactions of isonitriles with a variety of metalloboryl and metalloborylene species are shown to yield a range of products, none of which display the typical Lewis acid-base reactivity previously observed between such metal complexes and other Lewis bases. Insertions of one, or several, isonitriles into the metal-boron bond give cyclic and spiro compounds with bonding controlled by the electron count at the metal and in the ring.