We have shown the development of carbamoyloximes as a mechanophore class in which the mechanochemical reaction rates counterintuitively increase alongside the thermal and photochemical stabilities (Figure ). All carbamoyloxime mechanophores undergo homolytic bond scission under mechanochemical conditions and their mechanochemical reaction rates increase with the degree of substitution on the α-substituent, likely because of the destabilization of the N-O bond and the stabilization of the formed iminyl radical by hyperconjugation. Surprisingly, the mechanochemical reaction pathway diverges considerably from its thermal and photochemical counterparts. For carbamoylaldoximes, both heat and light induce a pericyclic syn elimination, thereby significantly decrease the activation energy, and subsequently render these mechanophores thermally and photochemically labile. For carbamoylketoximes, this pathway is not accessible and homolytic bond scission at the N-O bond dominates, although only from the T1 state.