This book deals with the synthesis of green fluorescent Nitrogen-doped Carbon Dots (N-CDs) through solvent-free pyrolysis, and their application in developing blue fluorescent nitrogen-doped silver (Ag/N-CDs) and copper (Cu/N-CDs) nanocomposites. These composites serve as highly efficient Uric Acid (UA) sensors, with fluorescence quenching visible to the naked eye. The quench in fluorescence is due to the synergistic effect between the fluorescence Inner Filter Effect (IFE) and the static quenching effect, with a Lower detection limit (LDL) of 4µM thus functioning as a highly rapid UA biosensor. The book highlights a simple, eco-friendly method for rapid UA detection without catalytic interference.