This work deals with all aspects of luminescent materials basic,applications and advanced developments.Solid state lighting is an emerging field of research.The book is focus on synthesis of nanophosphors and their applications. We have studied series of rare earth activators e.g., Ce3+, Pr3+, Sm3+, Eu3+, Eu2+, Gd, Dy, Yb in its bulk as well as nanocrystalline form has been synthesized. Material characterization by XRD and SEM was carried out and photoluminescence excitation and emission spectra were measured to explore the possibility of using these phosphors for solid state lighting applications using near UV/ blue LED.