Based on our measured redox potential of ynamides as shown in Scheme 1b (Figure ), we recognized that good candidates for a single electron photoredox catalyst should be capable of oxidizing ynamide in the range +1.5 to +2.0 V. And we envision that the use of a positively charged photoredox catalyst could minimize unproductive back electron transfer to ynamide radical cation via minimization of Coulombic attraction in the reduced (neutral) form of the catalyst. In light of these considerations, acridinium photoredox catalysts, which have been applied in a number of reported transformations relying on singleelectron transfer pathways, drew our attention. We predicted that 9-mesityl acridiniums photocatalysts possessing high excited state oxidizing power (Mes-Acr-Me + E1/2 red* = +2.12 V vs SCE) could conveniently catalyze ynamide radical cation generation, and the reduced form of the acridinium catalyst is a moderate single electron reductant (E1/2 ox = -0.57 V vs SCE) that could presumably return electron transfer to radical intermediate.