An efficient method for visible-light-initiated, nickel-catalyzed Sonogashira C­(sp)–C­(sp2) coupling has been developed via an energy-transfer mode. Thioxanthen-9-one as a photosensitizer could significantly accelerate the arylation of alkynes with a wide range of (hetero)­aryl halides in high yields. The cross-coupling reaction undergoes the stepwise oxidative addition of an arylhalide to nickel(0), transmetalation of the resulting aryl–Ni­(II) halide species with Zn­(II) acetylide into aryl–Ni­(II) acetylide species, energy transfer from the excited state of thioxanthen-9-one to aryl–Ni­(II) acetylide, and reductive elimination to the aryl alkyne.

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