A phthalazinetrione derivative, 2-(benzo[d]thiazol-2-yl)-4-hydroxyphthalazin-1(2H)-one hydrate (TP) was developed based on phthalic acid and 2-hydrazinobenzothiazole in acetic acid (AcOH) solution and obtained corresponding crystal TP-A. The TP-A exhibited colorimetric fluorescence response from yellow to green through fuming with the triethylamine (TEA) vapor, resulting in the crystal structure change to TP-N. TP-A and TP-N exhibited aggregation-induced emission (AIE) in solid state due to the J-aggregation and dimer formation, respectively. And the interconversion of the J-aggregation and dimer by a external TEA/AcOH vapor stimuli successfully and repeatedly realized switching of yellow/green luminescence. In addition, TP-A and TP-N showed similar AIE effect both in aqueous solution and in solid state, and they exhibited different sensing behavior in 100% aqueous solution. TP-A with excellent selectivity and sensitivity could be employed as a fluorescent colorimetric sensor to discriminately identify Zn²⁺ and Cd²⁺. TP-N could further fluorescent colorimetric sensing glutathione (GSH). Different aggregation pattern gave different chance for Zn²⁺/Cd²⁺.and GSH to respond with the formation of new aggregates through corresponding coordination reaction and addition reaction mechanism. Further, the TP-A and TP-N were applied to detect Zn²⁺/Cd²⁺.and GSH in Hela cells.