This book deals with the bio based catalytic system using the ash of waste material as the active catalyst. Keeping this idea in mind and in continuation of our interest in application of natural catalysts, herein we wish to report an Aegle marmelos fruit ash as an efficient and eco-friendly catalyst for synthesis of heterocycles. To the best of our knowledge, this is the first report on the use of bio-based water extract of bael fruit ash (WEBFA) catalyst for heterocycles synthesis even for any organic transformations. The catalyst was obtained by thermal treatment followed by water extraction of the rind of Aegle marmelos (bael) fruit. In our work we have developed some multi-component synthetic methodologies using natural 'feedstocks' dry rinds of Aegle marmelos (Bael) fruit ash for synthesizing vital heterocyclic structural motifs such as 2-amino-4H-chromenes, pyranopyrazoles, pyrazoly-4H-lchromenes, dibenzo[1,4]diazepinones, 1,5-benzodiazepines, benzylpyrazolyl coumarins, and pyrazolopyranopirimidine. We hope that BFA will find more applications in MCRs leading to biologically potent molecules in the near future.