The coupling reaction of terminal alkynes with organic halides, Sonogashira-(Hagihara) coupling, takes place with only 2 equivalents of dilute aqueous ammonia as ail additive. The reaction of phenylacetylene and 4-iodoanisole in the presence of 1 mol% of PdCl2(PPh3)(2), 2 mol% of CuI, and 2 equiv of aqueous ammonia in THF proceeds at room temperature for 6 h to afford the coupling product in a quantitative yield.