ACHE and lung cancer: To obtain ideal probes with favourable oil-water distribution coefficients (favourable membrane permeability), in this study, two intramolecular charge transfer (ICT) based probes BF2-cur-Ben and BF2-cur-But were designed with BF2-cur as the fluorophore and benzoyl ester and butyryl ester as the recognition groups (Figure 1), which is expected to enable the visualization and monitoring of overexpressed AChE during apoptosis in lung cancer.