The alkyl-bridged N-heterocyclic carbenes are attracting more research interest as a kind of potential eminent bidentate ligands.By changing the length of the alkyl linker,the molar ratio of the ligands to transition metals,or reaction conditions,they can form NHC metal complexes with different structure,featuring special photoelectric properties or catalytic activities.1-2 Here we report the synthesis and catalytic activity of methylene bridged chiral bis-NHC-Pd complexes.Using L-amino acids as starting material,methylene bridged di-imidazolium salts were obtained through amidation,cyclization,and quaternization by CH2I2.Direct metalation by PdCl2 afforded the chelate bis-NHC-Pd complexes(Figure 1).Initial study proved that the bis-NHC-Pd complexes exhibited good catalytic towards Pd-catalyzed Mizoroki-Heck reaction between 1,2-dimethylimidazole and 4-bromoacetophenone(Figure 1).