Quasi-homogeneous catalysis using nanoclusters(NCs)consisting of more than one metal so-called bimetallic NCs is seeing more widespread application in organic synthesis.We have used Au/Pd bimetallic alloy to activate the high-energy carbon-chlorine bond and found that the Au/Pd NCs could catalyze Ullmann coupling of chloroarenes at ambient temperature[1,2],a reaction that otherwise requires harsh conditions.Neither pure gold nor pure palladium clusters could catalyze the reaction,indicating that alloying of the metals was critical for reactivity.