Abstract: Three diketopyrrolopyrrole (DPP) derivatives D-PEO, D-Boc and D-C₁₂ were synthesized. They differ themselves in the substituents on the lactam nitrogen of DPP, three substituents are used, namely polyether chain, tert-butyl ester group and alkyl chain. The solutions of three DPP derivatives were drop-casted onto silica gel plates to prepare sensors for the detection of ethanol, methanol and water. The sensors can clearly distinguish ethanol, methanol and water with the naked eye. The principle is that the changes of the interactions (such as hydrogen bonding interaction, intermolecular aggregation, etc.) between the solvent analyte, the fluorescent molecule DPP and silica gel can cause the changes of the fluorescence colors and intensities of the sensors, so as to achieve the purpose for checking different polar solvents.