Herein, we report a Csp-Csp cross-coupling process involving the merger of gold catalysis and visible light photocatalysis leading to the alkynylative cyclization of -alkynyl benzoic acids. The corresponding and previously undescribed alkynylidenephthalide products were obtained as mixtures of : isomers. The key C-C bond formation is based on the photoactivation of the oxidative addition of an alkynyliodide to a vinylgold(I) intermediate resulting from an initial 5--dig cyclization pathway, as supported by mechanistic studies including DFT calculations.
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