Abstract

They are an interesting class of dicationic salts that find many applications in modern science and technology including electrochromic devices, molecular machines and organic batteries [1]. The viologen moieties impart a suite of properties including redox properties, ionic conductivities, thermochromism, photochromism, electrochromism and piezochromism that are the principal reasons for their versatile applications. They are used for the preparation of ionic liquids after suitable chemical modifications of these moieties of varied chemical architectures with the variation of numerous anions. These moieties even form ionic liquid crystals (ILCs) of suitable chemical architectures in combination of appropriate anions. Recently, ILCs is an active area of research in energyrelated systems including batteries and dye-sensitized solar cells to combat the global energy crisis. These salts are typically synthesized by the quaterization of 4,4- bipyridine with alkyl halides or alkyl tosylates i.e., the so called Menshutkin reaction.