Pristine MC emitters were ground by using a pestle in a mortar, then the powders were collected for measurement at room temperature. The crystalline solids of DCzPy were obtained by recrystallization in the mixture of chloroform and methanol. As shown in Fig. and, the pristine powders of DCzPy emitted blue-green fluorescence at 490 nm. The fluorescence quantum yields (QYs) of pristine crystalline powder DCzPy was measured to be 7.4%. Upon gently grinding with a pestle, DCzPy fluoresced sky-blue PL at 457 nm with a blueshift by 33 nm. At the same time, the fluorescence QY of DCzPy enhanced up to 24.1%, while the lifetime had no obvious change (τ = 4.95 ns) (Fig. and). Further heavily grinding the resultant micro-crystal fragments into tiny powders. Interestingly, the emission of the ground powders reverted to original blue-green light with an emission efficiency of 16.8%. To deeply understand the mechano-responsive behavior of DCzPy, the fluorescence rate constants were computed. The radiative decay constants (kr) of DCzPy from S1 to S0 increased from 1.49  10 7 s -1 in pristine powders to 4.87  10 7 s -1 after gently grinding, which implied that the emission efficiency is strengthened. Keep enhancing the anisotropic force, the kr of DCzPy changed to 4.97  10 7 s -1 , indicating a turn-on MC feature. Then, solid-state UV-vis spectra were performed to study their groundstate change. The absorption band showed small blue-shift with increasing the grinding force, which was coincident with the PL spectra shift (Fig. ). Moreover, the emission of the ground powders could return to their pristine state by recrystallization.