The reaction of complex (SIPr)PdCl 2 (TEA) (SIPr = 1,3-bis(2,6-diisopropylphenyl)-2-imidazolidinylidene, TEA = triethylamine) with tertbutylammoniun chloride (TBAC) at room temperature affords the new ionic complex [TBA][(SIPr)-PdCl 3 ] in quantitative yield. The activity of this complex as a precatalyst for Heck coupling reactions has been explored. Experimental results and DFT calculations support a plausible anionic Amatore−Jutand-type mechanism for the Heck reaction involving anionic (NHC)-palladium(0) catalytic species.