Lyso-Tracker Green is a fluorescent small-molecule probe designed specifically for labeling lysosomes in living cells. As a weakly basic fluorophore, it accumulates selectively in acidic cellular compartments, primarily lysosomes, due to protonation under low pH conditions. Unlike conventional dyes such as acridine orange or neutral red, Lyso-Tracker Green exhibits superior organellar selectivity and requires only nanomolar concentrations to produce robust fluorescent labeling. It is widely utilized in biomedical research for imaging lysosomal localization and analyzing cellular physiology in live-cell assays, but is not compatible with fixed-cell staining protocols.