Herein, in accord with the experimental evidence and literature support, a plausible mechanism is depicted in Scheme 4 using the reaction of 1a and pyrazole as an example. It is proposed that a reductive quenching of photoexcited Mes-Acr+* by 1a leads to ynamide cation radical I and the reduced Mes-Acr•. The resultant intermediate I undergoes regioselective nucleophilic addition with pyrazole giving vinyl radical intermediate II that could be stabilized by the adjacent aromatic resonance contribution. It is proposed that the cationic vinyl radical II is reduced by Mes-Acr• leading to the formation of a vinyl anion intermediate III and photocatalyst regeneration. We envisioned that, in this reaction, the vinyl anion is immediately quenched by intramolecular proton transfer producing pyrazole enamide 2a. The observed syn addition selectivity is rationalized by rapid proton transfer and proximity effect. The mechanism of this reaction is currently the subject of detailed investigations undertaken by our group. In sum, a photoredox catalyzed hydroamination of ynamide with various heteroaromatic compounds including pyrazoles, triazoles, and tetrazoles has been developed. By accessing reactive ynamide radical cation intermediate, this protocol provides convenient metal-free access to a variety of valuable α-heteroarene substituted enamides. Notably, this research disclosed a photocatalytic strategy for synthetically attractive alkyne radical cation generation from readily available ynamides, which provide a solution, at least in part, for the generation of highly reactive alkyne radical cation species, and therein holding the promise to advance this underdeveloped research area. Further investigation of the reaction mechanism and the synthetic applications are currently underway.