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Active species were introduced into MOFs to prepare multifunctional fluorescent probes by a stepwise postsynthetic modulation strategy. First, two-dimensional HPU-16 (HPU = Henan Polytechnic University; HPU-16 = Zn(L) 2 (H 2 O); HL = 2-(5-pyridin-4-yl-5 H -[1,2,4]triazol-3-yl)-pyrazine) was transformed into three-dimensional HPU-17 ({Zn 3 (L) 2 (btc) 2 (H 2 O)} n ) through a crystal dissolution-recrystallization process. Second, linker replacement was used to introduce -NH 2 into the HPU-17 to generate functional NH 2 -HPU-17 via a single-crystal to single-crystal transformation. The functional amino groups caused NH 2 -HPU-17 to show a significant response to ClO - . Because of the interaction of amino groups and ClO - , the fluorescence of NH 2 -HPU-17 gradually changed from blue to yellow-green. More interestingly, NH 2 -HPU-17 could encapsulate Tb 3+ and sensitize the visible-emitting characteristic fluorescence of Tb 3+ in aqueous solution. Then, newly generated Tb 3+ @NH 2 -HPU-17 could serve as an effective probe for the determination of DPA. This work paves a new way for the design and modulation of ratiometric fluorescence probes for the selective and sensitive detection of special molecules.