The team develops multifunctional fluorescent molecules and nanoparticles for biomolecular detection and imaging. We developed i) solvatochromic probes for ratiometric and super-resolution imaging of plasma membrane organization and cell polarity mapping, and ii) fluorogenic membrane probes operating from green to near-infrared range for imaging cells, tissues and organoids by advanced microscopy techniques. We also introduced environment-sensitive fluorogenic probes for imaging G protein coupled receptors and intracellular RNA. We also developed dye-loaded fluorescent polymeric nanoparticles (NPs) 100-fold brighter than quantum dots of similar size. They were successfully applied for single-particle tracking in cells and mice brains by intravital microscopy. Using NPs of different colors, we introduced a technique for barcoding of living cells. These NPs were also used as light-harvesting nanoantennas to prepare biosensors for cancer diagnostics and fluorescence in situ hybridization (FISH) for intracellular RNA imaging.