Description Aggregation-induced emission luminogens (AIEgen) were tailored to detect biological thiols. Maleimide is attached to the TPE core, giving TPE-Thiol.16. The reaction is inspired by the fast and efficient thiolene click reaction between maleimide and thiols, TPE-Thiol is not emissive in both solution and aggregated states, due to the photo-induced electron transfer from TPE to maleimide. However, reaction with thiol groups can interrupt the electron transfer process and turn-on the emission of TPE. TPE-Thiol can be used for labelling of protein carrying cysteine residues in the physiological media and poly(acrylamide) gel electrophoresis assays.TPE-Thiol is an aggregation-induced emission (AIE) material for the "Click" chemistry, with alkene and thio group detection.