Innovative Fluorescent Probes to Track Lipid Droplets and Endoplasmic Reticulum Dynamics

Abstract Lipid droplets (LDs) and the endoplasmic reticulum (ER) are dynamic organelles central to cellular metabolism, signaling, and stress response. Despite their biological relevance and close interplay, tools to selectively track their dynamic behavior remain limited. Here, the design, synthesis, and characterization of a new class of fluorescent probes obtained through green multicomponent synthetic strategies are reported. These previously unexplored fluorophore scaffolds display unexpected and differential subcellular localization, selectively targeting either LDs or the ER with high photostability. Mechanistic studies suggest that such selectivity arises from a synergistic interplay between partition coefficient, conformational geometry, and strategically positioned targeting moieties. These features enable the probes to adapt to distinct microenvironments within cells, supporting real‐time visualization of both LD and ER dynamics. These findings provide versatile sensing tools and novel insights into organelle‐targeting principles, establishing an eco‐conscious route to next‐generation fluorescent sensors.