Schiff base-derived chemosensors have emerged as highly versatile and tunable platforms for the selective optical detection of environmentally and biologically hazardous metal ions, particularly Al³+, Cu2+, and Hg2+. This review critically consolidates recent progress in imine-based ligand design, highlighting the strategic incorporation of heteroaromatic scaffolds, electron-donating coordination sites (-O, -N, and -S), π-conjugation rigidification, and intramolecular hydrogen-bonding architectures that precisely modulate metal-binding geometry and photophysical response. Special attention is devoted to mechanistic insights underlying signal generation, including chelation-enhanced fluorescence (CHEF), metal-induced quenching, PET/ICT regulation, ESIPT modulation, FRET-assisted ratiometric sensing, and aggregation-induced emission phenomena. Their performance in live-cell imaging is discussed in terms of intracellular stability, pH adaptability, photostability, and cytocompatibility, underscoring the translational potential of Schiff base sensors in environmental monitoring and biomedical diagnostics.
Udhayakumari Duraisamy (Mon,) studied this question.