Utilization of natural catalysts obtained from renewable resources is new and inexpensive method which can contribute to the development of new synthetic methodologies. This book, presents the applications of natural catalysts like calcined eggshells (CES) and Lemon juice for the organic syntheses. The use of CES catalyst reduces environmental problems and adds in making efficient use of natural waste material. Lemon juice catalyzed reaction provides a novel case of catalytic promiscuity which widens the applicability of Lemon juice in organic transformations. The book is divided into seven chapters. At the end of every chapter, corresponding IR, 1H NMR and 13C NMR spectra of representative compounds and full spectral data of synthesized compounds are provided. The limited and relevant references are retained to the literature of those research journals which are easily assessable. The book will be indispensable for the researchers majoring in organic chemistry in general to keep the track of recent research developments. It will also serve as the guide to the research investigators to get acquainted in newer areas of chemical sciences.