Synthesis of new fluorescent dyes and their spectroscopic studies attracts considerable attention due to their wider applications in material as well as biological fields. The results described in this book are produced from research work carried in our lab. This book provides valuable information about synthesis, reactions, fluorescence and liquid crystal properties of various new class of coumarin and benzocoumarin fluorescent dyes. The fluorescence spectra were recorded in chloroform, acetonitrile and ethanol for all compounds and they emit blue light in the range 450-500 nm. The results revealed that some of the compounds exhibited high quantum yield in ethanol when compared to standard Rhodamine B. Hence this book includes some important fluorescent dyes which could be very useful in material and biomedical applications.