Can we further deviate from the octet rule by removing one or two of the non-bonding electrons from the carbene center? This would lead to either a carbene radical cation or a carbene dication (Fig. ). Early studies showed that the diphenylcarbene radical cation (Ph2C •+ ) can be transiently generated by single-electron oxidation of diazodiphenylmethane (Ph2CN2) followed by N2 liberation, and could be spectroscopically characterized (Fig. ) . More recently, attention has shifted to the oxidation of stable singlet carbenes since they possess a more electron-rich carbon center . Several groups have systematically explored the oxidation of N-heterocyclic carbenes (NHCs) and cyclic (alkyl)(amino)carbenes (CAACs) with various single-electron oxidants . In all cases the reaction afforded the conjugate acid of carbenes (Fig. ). It was proposed that this was the result of the generation of the desired carbene radical cations that abstract H• from the solvent . NHC radical cations have also been invoked as key intermediates in the emerging field of NHC single-electron transfer catalysis, but never spectroscopically observed, clearly suggesting that they are only short-lived intermediates .