The chemistry of transition-metal complexes containing N-heterocyclic carbenes (NHCs) has been extensively studied, and a large number of compounds have been reported. Among various metal complexes, the Ag-NHC complexes turned out to be very unique, since they are fluxional molecules and also efficient carbene-transferring reagents. The structures of these complexes were also interesting, and many examples have been reported in the literature. 1 The compounds could be readily prepared by the reaction of the imidazolium salt with Ag 2 O, and it is not necessary to isolate NHC, which is a less stable species. Interestingly, few 1:1 complexes were reported, 2 while a series of 2:1 (Ag 2 (bis-NHC)) complexes 3,4 and 2:2 (Ag 2 (bis-NHC) 2 ) complexes 5-7 were characterized. Even cyclic bisimidazolium salts reacted with Ag 2 O to give interesting 2:2 complexes. 8 Many of these Ag-NHC complexes were known as good carbenetransfer agents, and various metal-NHC complexes have been synthesized. Among the complexes, the Pd-NHC complexes 9 have been extensively studied since the complexes are potentially useful catalysts for organic synthesis. In contrast to the corresponding Ag-NHC complexes, a limited number of dinuclear Pd complexes have been reported in the literature. 10 We have been interested in the chemistry of metal-bis-NHC and metal-NHC-oxazoline complexes and synthesized some Pd complexes with unique structures. 11 In this paper we report the synthesis and structure of new dinuclear silver and palladium complexes that are connected with 2,7-dimethylnaphthalenebridged bis-NHC ligands. 11 The catalytic activities of the Pd complexes were also examined.