To test the principle, we subjected ynesulfonamide 1a (E1/2 ox = +1.44 V vs SCE) and pyrazole (1.0 equiv) to 5 mol% of 9-mesityl-10-methylacridinium perchlorate (Mes-Acr-MeClO4) in acetonitrile under irradiation with 450 nm LEDs at room temperature. The desired hydroamination adduct (Z)-2a was obtained in 72% yield in 6 hours with high syn addition selectivity (Z/E = 11:1). The structure of (Z)-αpyrazole enamide 2a was unambiguously identified spectroscopically and confirmed by X-ray crystallography. Only unconverted starting materials were recovered when the reactions were carried out without photocatalyst or photoirradiation (Table , entries 2 and 3). It is worthy that inert gas protection is not necessary for the reaction (entry 4). Increasing reaction time to 12 hours did not improve the production of 2a, instead, photoinduced Z → E isomerization was observed (entry 5, 12 hrs, Z/E = 2.1:1). Systematic examination of the reaction variants, including photocatalysts and solvents, were performed. Neither iridium (Ir[dF(CF3)ppy]2(dtbbpy)PF6),nor ruthenium ([Ru(bpy)3][PF6]2) photocatalysts were effective catalysts for this reaction (entries 6 and 7). Mes-Acr-PhBF4 is comparable to Mes-Acr-MeClO4 giving 2a in 70% yield (entry 8). The use of toluene or acetone also delivered the formation of 2a, albeit in low to moderate yield (entries 9 and 10). Methanol and dimethylformamide were not suitable solvents for this transformation (entries 11 and 12). The optimized reaction condition was identified as the use of Mes-Acr-MeClO4 in dichloromethane with 1.2 equiv. of pyrazole (entry 14), providing the best results to date (5 hours, 83% yield, Z/E = 12:1). Having identified a viable catalyst system, we investigate the substrate generality of ynamides and pyrazoles for the photoredox catalyzed intramolecular hydroamination reaction. A variety of ynesulfonamide with various substitution patterns and functional groups were examined in the reaction with pyrazole (Table ). Ynesulfonamides bearing electronically distinct aryl substituents ranging from electron-rich (2b and 2c) to electron-deficient (2d, 2e, and 2f) provided the desired (Z)-α-pyrazole enamides in good yields and high selectivity (Z/E > 10:1). The reactions of N-Bn-and N-t Bu-ynesulfonamides with pyrazole generated products 2g and 2h smoothly in high yields. It is noteworthy that the photoinduced Z → E isomerization of (Z)-α-pyrazole enamide 2h was not observed with prolonged reaction time (up to 18 hours), presumably because of resistance to isomerization caused by steric effect of bulky tert-butyl group. N-Mesyl and N-nosylynamides gave high yields of the corresponding products 2i and 2j as well. 3-(Phenylethynyl)-2-oxazolidinone (E1/2 ox = +1.75 V vs SCE) was a suitable substrate as well, yielding product 2k in 69% yield with high Z/E selectivity (> 15:1). The scope with respect to substituted pyrazoles was then explored. In contrast to the high reactivity of 4substituted pyrazoles (2l, 2m, and 2n), reaction yields of 3-substituted pyrazoles were significantly diminished (2o and 2p), and steric interactions are probably responsible for the poor activity of the 3substituted substrates. The reaction was further tested with alkyl substituted ynamide. Employment of hexyl substituted ynamide gave -pyrazole enamide 2q as a major product albeit with a lower isolated yield. Azoles are a privileged structural motif in many bioactive and pharmaceutical compounds and have versatile applicability as building blocks for synthesis and catalysis. We were able to employ a diverse range of N-heterocyclic nucleophiles directly coupled to ynamide in our reaction protocol, thus providing access to potentially valuable nitrogen heterocycles bearing enamide moiety (Table ). In addition to pyrazoles, good reactivities between ynamides and triazoles, benzotriazoles, indazoles, and tetrazoles were observed. Products with substitution at N1 of 1,2,3-triazoles and benzotriazoles were yielded as the major regioisomer as expected (3a-3g), which is a result of the statistical advantage and increased electron density of N1/N3 over N2. The reaction selectivity and product structure were unambiguously identified spectroscopically and confirmed by X-ray crystallography for 3e. Indazole gave a single N2 regioisomeric product (3j-3l), which is confirmed by X-ray crystallography analysis of product 3j. Exclusive (Z)-α-tetrazole enamides 3m and 3n were produced from the reaction of 5-methyl-1H-tetrazole in a 3.8:1 N2:N1 N-regioisomeric ratio, congruent with prior observations of hydroheteroarylation of ynamides with 2H-tetrazoles under thermal conditions. The reaction class presented here should be of potential interest to the biomedical community as a tool for bioactive molecular synthesis and lead-drug candidate discovery.