3-Trifluoroacetylchlorin possessing an omega-aminoalkyl chain at the 17-propionate residue was prepared to realize a chlorophyll-based supramolecule acting as a thermochromic switch. A THF solution of the synthetic sensor molecule appeared brown, while the solution color became purple at lower temperature due to the conversion of the trifluoroacetyl group to its alpha-amino alcohol adduct form in a molecule.