The respective substituted N-phenyl thiosemicarbazide (~300 mg) was suspended in absolute ethanol (10 mL) and the mixture was treated with 4-butylbenzaldehyde (~1.1 equivalent) and stirred at room temperature under nitrogen atmosphere for > 8 h. The products were re-precipitated with a solvent mixture of H2O/ethanol and were collected by filtration. Compound 9 was purified by column chromatography with silica gel and 1:1 ethyl acetate/hexane as the eluent. Characterization data for transporters 1-9 is provided in Supplemental Material.