An amphiphilic ruthenium(II) cyano complex, (N(C2H5)(4))(2)-[Ru(dc18bpy)(CN)(4)] (dc18bpy = 4,4 ' -dioctadecyl-2,2 ' -bi-pyridine), was prepared by photo-induced ligand exchange. The X-ray diffraction patterns were compared before and after the electrochemical oxidation of the cast film on an ITO electrode. The film had a layered structure, whose interlayer distance changed irreversibly from 4.60 nm to 3.01 nm when the central Ru(II) ion was oxidized to Ru(III).