Here, in the present work, a new hydroxybenzothiazole derivative (HBT 2) with AIE+ESIPT features was synthesized by Suzuki–Miyora coupling of HBT 1 with 4-formylphenylboronic acid. The AIE and ESIPT features were confirmed by optical, microscopic (AFM) and dynamic light scattering (DLS) techniques. The yellow fluorescent aggregates of HBT 2 can specifically detect Cu2+/Cu+ ions with limits of detection as low as 250 nM and 69 nM. The Job’s plot revealed the formation of a 1:1 complex. The Cu2+ complexation was further confirmed by optical, NMR, AFM and DLS techniques. HBT 2 was also used for the detection of Cu2+ ions in real water samples collected from different regions of Punjab. HBT 2 was successfully used for the bio-imaging of Cu2+ ions in live A549 and its anticancer activity was checked on different cancer cell lines, such as MG63, and HeLa, and normal cell lines such as L929. We successfully utilized HBT 2 to develop security labels for anticounterfeiting applications.

A pseudo‐Crown ether (open chained podand) containing two rigid and bulky perylene diimide units as terminal end‐group (diPDI 2) has been synthesized. The diPDI 2 selectively binds with Pb2+ ions to form 2 : 1 sandwich type complex (Job's plot, NMR and SPECFIT) in solution. The complexation led to significant changes in fluorescence and absorbance; in NMR chemical shifts (Δδ=0.5–0.6 ppm) and in size of the aggregates (DLS, AFM). We further demonstrated formation of diPDI 2‐Pb2+ host‐guest supramolecular complex using Cyclic voltammetry (CV), powder X‐ray diffraction, thermogravimetry (TGA), Infrared, Raman spectroscopies. The Hill coefficient (nH) value of >3.7 indicates cooperativity in Pb2+ binding process at high concentrations. We also demonstrated utility of diPDI 2+Pb2+ complex in a ‘turn‐on’ sensing of biological relevant amines such as spermine and diethanolamine (DEA) using displacement approach. The dissociation of diPDI 2+Pb2+ complex with these amines via sequestration of Pb2+ results in restoration of optical and NMR chemical shift signals. The reversibility of diPDI 2+Pb2+ complex with DEA offers fabrication of IMPLICATION logic gate.

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