NAD (Nicotinamide adenine dinucleotide) is a ubiquitous biomolecule found in all living organism and exists in two different forms -the reduced form (NADH) and the oxidized form (NAD + ). NADH functions as a coenzyme in the metabolic processes such as glycolysis, tricarboxylic acid cycle and pentose phosphate pathway. Besides, NADH is also extensively involved in various physiological processes. For example, energy metabolism, cell death and aging, mitochondrial respiration chain, gene expressions, antioxidation and biosynthesis. Therefore, alternation in the NADH levels inside the cells is indicative of certain critical pathological conditions in our body such as diabetes, depression, Alzheimer's disease, cancer and Parkinson's disease. To understand such pathological and physiological conditions, intracellular tracking and imaging of NADH levels can be of vital importance.