A displacement method of detecting hydrogen sulfide in aqueous media based on complex L-Cu ensemble is developed. Once combined with Cu2+, complex L-Cu displayed high specificity for sulfide anion. Among the various anions, only sulfide anion induce the revival of fluoresecence of compound L, which is quenched by Cu2+, resulting in turn-on type sensing sulfide anion. Complex L-Cu exhibits a highly sensitive fluorescent response toward S2- by releasing compound L to give a remarkable change with 20-fold fluorescence intensity enhancement under 2...