ABSTRACT: The mechanofluorochromic properties of three C6-unsubstituted tetrahydropyrimidines (THPs), namely, diethyl 1,2,3-triphenyl-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (1), dimethyl 1,2,3-tri(4-trifluoromethylphenyl)-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (2), and dimethyl 1,2,3-tri(3-trifluoromethylphenyl)-1,2,3,6-tetrahydropyrimidine-4,5-dicarboxylate (3), with aggregation-induced emission (AIE) characteristics were investigated. The blue-green/cyan emissions of the three THPs can be switched reversibly by a grinding-fuming/heating process, with the change in maximum emission wavelength (λ em) up to 57 nm and the decrease of fluorescence quantum yields (Φ F). Interestingly, the green or cyan fluorescence of the ground powder (λ e
