Organic solid-state emissive materials have gained much attention in recent times due to their excellent optoelectronic properties leading to successful commercialization for organic electronics.

A new salicylaldehyde appended fluorene-based chemodosimeter (FSal) has been designed by taking consideration of the special nucleophilicity of cyanide ion. FSal shows selective affinity towards CN⁻ over other anions (namely F⁻, Br⁻, NO₃ ⁻, ClO₄ ⁻, N₃ ⁻, H₂PO₄ ⁻, AcO⁻, I⁻, Cl⁻, and NO₂ ⁻) through turn-on fluorescence with a minimum detection limit of 0.06 ppm. The turn-on fluorescence of the FSal–CN complex resulting from hampering ESIPT is also supported by DFT and TDDFT calculations. Biological compatibility and live cell imaging of this unique probe have also been explored.