This book is based on the recent advancement of the functional materials includes graphene oxide, polyaniline, montmorillonite K10 which can be used various applications. For example, graphene oxide/poly(methyl methacrylate) gel electrolyte for the quasi-solid-state dye sensitized solar cell. Subsequently, reduced graphene oxide/polyaniline aerogel is utilized for supercapacitor application. Further graphene oxide is used for the preparation of jatropha oil based epoxy resin nanocomposite for coating application. In authors opinion this book will be helpful for understanding the recent applications of functional materials.