An electrochemical and computational study of a series of three 4-methyl-4＇-nonadecyl-1,1＇-bridged-2,2＇-dipyridinium ions is reported. In 0.1 M KCl these ions self-assemble on glassy carbon to form a close-packed monomolecular layer. Incorporation of perchlorate into the film by counterion exchange results in enhanced film stability and limiting surface coverages of ca. 1.7 x 10(-10) mol cm(-2). As the 1,1＇-bridge length is increased from two to four methylene groups, the reversible one-electron reduction potential of the dipyridinium head group decreases from - 499 to - 833 mV vs. Ag\AgCl\0.1 M KCl. These relatively negative reduction potentials make adsorbed 1,1＇-bridged-2,2＇-dipyridinium amphiphiles powerful immobilized reductants in aqueous solution. The catalytic potency of these amphiphiles is demonstrated by catalyzing the reduction of ethyl 3-benzoyl acrylate and artemisinin.