We hypothesized that the key to success for this methodology relies on the formation of an electrophilic radical cation species via the single-electron oxidation of alkynes (Scheme 1). While the direct anodic oxidation of phenylacetylene (1a, E ox p/2= +2.35 V) in acetonitrile (2a) indeed gave rise to the desired cycloadduct 3a, the yield was only moderate (Table , entry 2). Taking learnings from the success of triarylamines as redox mediators in electrochemical reactions, 29 we employed TPA (8 mol%) in a catalytic loading to facilitate the process (cf mechanistic discussion, vide infra), which gratifyingly doubled the yield of 3a (Table , entry 1). TPA, together with tetrabutylammonium hexafluorophosphate ( n Bu4N . PF6, 0.15 M) as electrolyte, was optimal, contrasting other combinations tested (Table 1, entries 3-5). Equally important was the employment of benzoic acid as a sacrificial reductant that generated hydrogen on the cathode, while other proton sources proved less effective (Table , entries 6-8). Furthermore, the choice of the electrode material was crucial: Best results were obtained with a reticulated vitreous carbon (RVC) anode -a microporous, glassy carbon electrode materialand a platinum cathode. A graphite plate was also acceptable as anode, albeit giving a slightly lower yield, while a graphite plate as both electrodes gave no reaction (Table , entries 9-10). Decreasing the reaction time or increasing the current decreased the product yield (Table 1, entry 11-12). Divided cell experiments emphasized the benefits of an undivided cell and its operational simplicity (Table , entry 13). No product was obtained by constant potential electrolysis controlling the anodic potential at +1.3 V, whereas 3a was obtained in 23% yield by applying a constant potential of +2.5 V (Table , entry 14). We, therefore, concluded that the anodic oxidation of the alkyne is essential to initiate the cycloaddition reaction. An inert atmosphere was important (Table , entry 15), and moreover, no product formation without electricity passed excluded the possibility of a background reaction (entry 16). With the optimized conditions in hand, we examined the scope of the reaction (Scheme 2). Phenylacetylenes with moderately electron-donating (Alkyl) and electron-withdrawing (para-F, Cl, Br) groups allowed the coupling with 2a, giving rise to 3b-i in good to high (51-78%, Scheme 2a) yields. The structure of pyridine 3i, which proved valuable for further transformations (vide infra, Scheme 4), was confirmed by single crystal X-ray analysis. A phenyl acetylene derivative with a strong electron-donating group at the para-position (p-OMe) was also coupled successfully, however, in this case pyridine 3j could be obtained without the TPA additive. Alkynes containing stronger electron-withdrawing substituents (4-carboxylic ester, 4-trifluoromethyl, 3,5-disubstituted halides (F, Cl)) were found to be unreactive (3k-3n), suggesting that their initial electrochemical oxidation to a radical cation is not possible under these conditions (cf mechanistic discussion, vide infra).