After evaluation of the cytotoxic behaviour of the probe, the probe's ability toward tracking the intracellular NADH expression was examined. In the present study, HepG2 cells were treated 10 μM of probe concentration without using any additional permeabilizing agent. Post two hours of staining with the probe, it was observed that the probe is able to image green and red fluorescence due to presence of NADH in HepG2 cells in two different channels-the green and the red channel respectively (Fig. ). inhibits the activity of key glycolytic enzymes such as glyceraldehyde phosphate dehydrogenase (GAPDH). GAPDH catalyses the conversion of glyceraldehyde-3-phosphate to 1,3-bisphosphoglycerate. During this transformation, NADH is produced by the reduction of NAD + . Thereby, inhibition of GADPH in the glycolytic pathway can lead to decreased levels of reducing equivalent NADH. Also, the glycolysis pathway is the cytosolic source of NADH production and NADH being a cofactor plays crucial rule in glycolysis. Ultimately, when 3-BrPA targets GAPDH, it also affects the intracellular NADH levels. (Fig. ). Stokes shift which indeed a highly desirable property of any optical probe to be used for cellular imaging.