To improve the selectivity of probes, the following approach can be used that has not yet been reported in the literature: a "clickable" moiety (i.e., alkyne) at the carbamate warhead is transferred and pseudo-irreversibly bound in the ChE active site, while the unbound inhibitor and the leaving group can be effectively removed by washing, leaving only the "clickable" alkyne on the protein of interest to be labelled in the next step via the copper(I)-catalysed click reaction (i.e., copper-catalysed azide-alkyne cycloaddition) with an azide-functionalised fluorophore (Scheme 3). In situ click chemistry has already been shown to be a valuable tool in the discovery of potent AChE inhibitors. Scheme 3: The proposed labelling of ChEs with a carbamate warhead and subsequent coppercatalysed azide-alkyne cycloaddition click derivatisation with a fluorophore. Scheme 4: General synthetic route from disubstituted amines to carbamate end compounds.