synthesis of a peptide-containing lasso molecular switch by a self-entanglement strategy is described. The interlocked rotaxane molecularmachine consists of a benzometaphenylene[25]crown-8 (BMP25C8) macrocycle surrounding a molecular axle. This molecular axle contains a tripeptidic sequence and two molecularstations: a N-benzyltriazolium and a pH-sensitive aniliniumstation. The tripeptide is located between