Monitoring and visualization of complex physiological or cellular processes using fluorescence probes/biosensors is the ultimate goal of fluorescence bioimaging. Herein, several fluorescence probes/biosensors have been developed for the detection and analysis of biomolecules (or biomarkers) to monitor several physiological processes and diagnose disease (Acc. Chem. Res., 2019, 52, 2571). Several probes were developed to selectively target various biologically relevant analytes such as biothiols, hydrogen sulfide, formaldehyde, hypochlorous acid, zinc, pyrophosphate and fluoride ions (Dyes and Pigments, 2013, 99, 308; Anal. Chem., 2015, 87, 1188; Chem. Commun., 2016, 52, 124; Org. Biomol. Chem., 2012, 10, 8410; Chem. Commun., 2012, 48, 10243; Chemical Society Reviews, 2015, 44, 4367) as well as disease biomarkers such as amyloid-beta (for Alzheimer’s disease; Journal of the American Chemical Society, 2015, 137, 6781) and dipicolinate (for Anthrax; Asian Journal of Organic Chemistry, 2017, 6, 1257). Each of those probes were further applied to visualize various biological processes through two-photon bioimaging. A simple fluorescence assay kit for detection of antibiotic (ciprofloxacin) in urine has been developed, which is highly promising to avoid the drug overdoses in human body and reduce the drug contamination in environment (Sensors, 2016, 16, 2065).

The research of this sensing field has been further extended towards more rigorous applications in chemical biology as well as for environmental analysis (Anal. Chem. 2017, 89, 3724; Chem. Comm., 2017, 53, 10800; J. Mater. Chem. B, 2018, 6, 4446; Sensors and Actuators B-Chemical, 2018, 277, 576; Tetrahedron Lett., 2018, 59, 49; J. Anal. Method Chem., 2018, 2654127; Sensors and Actuators B-Chemical, 2019, 279, 204) through research collaboration with several renowned research groups (Cell Metab., 2017, 25, 1320; Phy. Chem. Chem. Phy., 2017, 19, 12237; RSC Adv., 2019, 9, 35549; Chem.–European Journal, 2019, 9728; Langmuir 2019, 35, 13, 4682) from academic institutions such as Harvard University (USA), Singapore National University (Singapore), S N Bose National Centre for Basic Sciences (India), West Bengal State University (India).

**One of the developed fluorescent probes for hydrogen sulfide is also commercialized by Merck Inc., USA.