A series of designed palladium biscarbene complexes including saturated and unsaturated N-heterocyclic carbene (NHC) moieties have been prepared by the carbene transfer methods. All of these complexes have been characterized by H-1 and C-13 NMR spectroscopy as well as X-ray diffraction analysis, The reactivity of Pd-C-(saturated NHC) is distinct from that of Pd-C-(unsaturated NHC). The Pd-C-(saturated NHC) bonds are fairly stable toward reagents such as CF3COOH, AgBF4 and I-2, whereas Pd-C-(unsaturated NHC) bonds are readily cleaved under the similar conditions. Notably, the catalytically activity of these palladium complexes on Suzuki-Miyaura coupling follows the order: (sat-NHC)(2)PdCl2 > (sat-NHC)(unsat-NHC)PdCl2 > (unsat-NHC)(2)PdCl2.