The cleavage of a Csp3−H bond by an N/B frustratedLewispair (FLP) is reported. Upon mild heating, the ambiphilic molecule (2‐NMe2‐C6H4)2BH activates the C−H bond of a methyl group in α position of a nitrogen atom to generate an unprecedented N–B heterocycle. Upon further heating, the novel species rearranges through a hydride abstraction/1,2‐aryl shift sequence. The mechanistic details of these transformations