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In this study, we newly synthesized iron phthalocyanine incorporated iron metallo-supramolecular polymers (Pc-Fe-polymer) and investigated its electrochromic behavior in both solution and solid-state devices. The presence of a terpyridine-attached iron phthalocyanine (FePc-TP) spacer revealed long-wavelength absorption at 670–700 nm, and the metal-to-ligand charge transfer (MLCT) by Fe-terpyridine coordination induced another absorption at 578 nm. Consequently, the Pc-Fe-polymer covered broad ranges of visible and near-infrared regions. Furthermore, due to facile charge delocalization during the Fe2+ to Fe3+ redox process, the Pc-Fe-polymer exhibited enhanced electrochromic performances. The Pc-Fe-polymer film experienced reversible electrochromic switching by changing the color from dark blue to transparent green in both solution and solid-state devices using LiClO4 as an electrolyte. The Pc-Fe-polymer exhibited exceptionally high switching stability (>1000 times) and a high coloration efficiency of 346.7 cm2/C and 211.4 cm2/C in solution and solid-state devices, respectively. Besides, we successfully demonstrated the feasibility of applying the Pc-Fe-polymer for flexible electrochromic devices on a plastic substrate. This study’s results suggest a designing concept for electrochromic materials that have highly stable and efficient switching for smart display and window applications.

A triple action chemosensor (R1) bearing a rhodamine and thiophene moiety was synthesized by a simple condensation reaction. The sensing behaviour and selectivity of the synthesized chemosensor toward metal ions were studied by UV-Vis and fluorescence spectroscopy. The chemosensor recognized Cu and Cr ions with significant changes in UV-Vis absorbance and fluorescence intensity. The results showed that Cr induced greater fluorescence enhancement whereas Cu ions bound strongly with the receptor by showing a strong absorption band at 554 nm but with weak fluorescence. A visible colour change was observed by the addition of Cu and that colour change is due to the opening of the spirolactam ring triggered by the addition of Cu ions. Job's plot analysis indicated a 1 : 2 and 1 : 1 binding stoichiometry between the chemosensor and Cr/Cu. Subsequently, the R1 - Cu complex chemosensor was employed to detect CN in the presence of different anions, such as F, Cl, Br, I, AcO, HPO, HSO, NO and OH. In addition, the live cell imaging of HeLa cells using R1 and Cr was demonstrated successfully.

Phenazine fluorophore based imidazole derivatives (S1 and S2) were synthesized and sensor studies were carried out with various cations. Aggregation induced emission (AIE) was observed selectively for Al among other cations under study in case of both sensors. H NMR titration supported the aggregation induced emission of S2 with Al. ESI mass spectra successfully confirmed the aggregate formation. SEM images clearly showed the aggregation of receptor induced by Al in a flower-like fashion. AIE probe was successfully applied for bio-imaging of RAW264.7 cells.

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