ESIPT‐AIE Active Schiff Base Fluorescent Organic Nanoparticles Based on 2‐(2‐(4‐(4‐bromo Phenyl) Thiazol‐2‐yl)Vinyl)Phenol (BTVP) Utilized as a Multi‐Functional Fluorescent Probe

Abstract The present study reports the synthesis and characterization of Aggregation‐Induced Emission (AIE) – Excited‐state intramolecular proton transfer (ESIPT) active 2‐(2‐(4‐(4‐bromo phenyl) thiazol‐2‐yl)vinyl)phenol (BTVP). The AIE properties of BTVP in Acetone/Water solution are investigated, and fluorescent organic nanoparticles (FONs) (sizes ranging from 150–200 nm) are prepared in various water fractions (f H2O ). The established visco‐chromic property suggests that the restriction of intramolecular rotation is responsible for the AIE‐ESIPT behavior of the molecule, providing a means to sense viscosity. The synthesized FONs act as fluorescence chemosensors to detect Al 3+ ions via a photoinduced electron transfer (PET) mechanism. Job's, Benesi–Hildebrand method, and 1 HNMR titration confirm the 1:1 binding of BTVP with the metal ion. Studies on the emission concerning pH reveal the high stability of FONs over a broad range of pH, and a gradual change in the emission wavelength for the BTVP‐Al 3+ complex (BTVP‐Al) is observed, providing a means to sense pH ranging from 2–8. The solid‐state photoluminescence of BTVP is used for latent fingerprint detection, demonstrating its efficiency in detecting both primary and secondary information. Additionally, both BTVP FNOs and BTVP‐Al are used in cell imaging, where specific nuclear staining with BTVP‐Al and cytoplasm staining with BTVP are observed.