1-Ferrocenyl　methyl-2-ferrocenyl-3-methylbenzimidazolium　iodide　(3)　and　1-ferrocenyl　methyl-2-ferrocenyl-3-ethylbenzimidazolium　iodide　(4)　have　been　synthesized　and　fully　characterized　by　MS,　IR,　1H　NMR,　13C　NMR　and　elemental　analysis.　The　structure-property　relationship　was　investigated　based　on　single　crystal　X-ray　diffraction　analysis,　UV-Vis　spectroscopy,　electrochemical　measurements　and　density　functional　theory　calculations　(DFT).　The　mechanism　of　the　electron　transfer　of　3　has　been　studied　by　DFT.　Their　catalytic　effect　on　the　thermal　decomposition　of　ammonium　perchlorate　(AP)　was　investigated　using　differential　scanning　calorimetry　(DSC)　and　thermogravimetry　(TG).　The　results　from　DSC　and　TG　analysis　indicate　that　3　and　4　are　of　high　catalytic　effect　on　lowering　the　decomposition　temperature　of　AP.　We　expect　that　the　novel　benzimidazole-bridged　dinuclear　ferrocenyl　derivatives　would　have　great　value　in　preparing　high-burning-rate　catalyst　for　composite　solid　propellants.　©　2013　Elsevier　B.V.　All　rights　reserved.