The chemistry of acridine and its derivatives has been studied for over a century owing to their diverse biological activities viz., antitubercular, antimalarial, antitumour, vasorelaxing, antiviral etc. Polyhydroacridine-1,8-diones are polyfunctionalized 1,4-dihydropyridine type derivatives. 1,4-Dihydropyridines (1,4-DHPs) are well-known compounds because of their biological activities. The chemical modifications on the DHP ring, such as different substituents or heteroatoms, have allowed the study of the extended structure and activity relationship and also provided some insight into the molecular interactions at the receptor level. In this context, polyhydroacridine-1,8-diones are also increasingly receiving attention due to their likeness in properties with those of 1,4-dihydropyridines. The aim of this book is to provide a brief knowledge about synthesis and medicinal importance of acridines and polyhydroacridines.