Mitochondria, often referred to as cellular powerhouses, play a vital role in numerous cellular processes. These range from cellular energetics, being essential for survival and growth, to triggering cell death through apoptosis induction ) . This double membrane organelle efficiently produces Adenosine Triphosphate (ATP) through oxidative phosphorylation (reviewed in ). Mitochondria are involved in controlling intracellular calcium and Reactive Oxygen Species (ROS) levels, which in turn can modulate various signaling events ) . Therefore, mitochondria are also considered to be signaling organelles. Increasing evidence suggests that the dysfunction of this multifaceted organelle can lead to several diseases across the physiological spectrum, including neurodegenerative diseases(Area-Gomez et al. ). An important issue to consider is that mitochondria are highly dynamic, rapidly changing with cell metabolism and signaling through fusion-fission (Bereiter-Hahn and Vöth 1994)changes in membrane potential (Chen L B 1988; Zorova 2018), ROS (reviewed in ) and fluidity ) . Further, there are multiple processes that shape different structural and functional aspects of the mitochondria. Therefore, smart probes are necessary for real-time monitoring of mitochondrial state, function and stress/damage. Here, environment-sensitive fluorescent chemical probes offer unique new opportunities for effective and multi-pronged mapping of mitochondrial state when coupled with fluorescent imaging, yielding spatial and temporal information in live cells and tissues Thus far, most studies use Mitochondrial Membrane Potential (MMP) as a proxy for measuring mitochondrial activity in living cells(Santo-Domingo and Demaurex 2012), especially if spatial and temporal information is desired at the cellular and tissue level. MMP is also sometimes considered as an important parameter for monitoring mitochondrial health . The assumption here is that MMP is indicative of ability of the mitochondrial to generate ATP via the gradient generated at the IMM as postulated by the chemi-osmotic theory (Peter Mitchell 1961; ). However, a careful reading of the theory suggests that MMP (ΔΨ) is just one of the two components that constitute the electro-chemical gradient (Δp); the main driving force behind ATP generation for instance. In fact, the electrochemical potential (Δp )is composed of an electrical part (ΔΨ, MMP) and a chemical part (∆pH) which in effect is the chemical gradient of protons generated by the ETC(Peter Mitchell and Moyle 1967; P. . ETC pumps protons from matrix side of the IMM to intermembrane space thereby generating a chemical gradient apart from an electrical gradient (which is contributed by distributions of "all" ionic species and not just protons). Therefore,