Palladium nanocolloids supported on chitosan behave as very efficient heterogeneous catalysts in the Heck reaction of aryl bromides and activated aryl chlorides in tetrabutyl-ammonium bromide as solvent and tetrabutylammonium acetate as base. Only 15 min is required to convert bromobenzene or p-nitrochlorobenzene into cinnamates. The efficiency of this catalyst is due to the stabilization of Pd colloids by the solvent and to a very fast PdH neutralization by the base. In contrast, no reaction occurs when utilizing imidazolium-based ionic liquids. The stability of the catalyst allows an extensive recycle in the coupling of iodoaromatics with butyl acrylate.