Natrajan's group develops luminescent lanthanide complexes for chemical and biological sensing. Research directions: (1) Time-gated lanthanide luminescence sensing — long-lifetime Eu3+, Tb3+, and Yb3+ complexes with millisecond emission lifetimes for background-free sensing in cells and tissue; (2) Intracellular sensing — luminescent probes for sensing O2, pH, viscosity, and specific enzymes inside living cells with spatiotemporal resolution; (3) Chiral discrimination — circularly polarized luminescence (CPL) from Eu3+ complexes for enantioselective sensing; (4) Responsive probes — switchable lanthanide complexes as ratiometric sensors for biomedical imaging. The long-lifetime emission enables time-gating strategies analogous to quantum sensing protocols.