Abstract: Novel fluorescent compounds based on dicyanomethylene-4H-pyran and benzothiadiazole scaffolds，responding to combinations of Cu²⁺，F^- and/or Br^- in a sequence dependent manner were synthesized and their recognition properties were investigated. Addition of Cu²⁺ immediately resulted in the "blue shift"，introduction of Br^- after Cu²⁺ has no detectable influence compared to Cu²⁺ ion alone，whereas F^- leads to complete quenching of fluorescence；In contrast，addition of F^- before Cu²⁺ induced only a slight reduction of fluorescence intensity at ca. 608 nm，while addition of Cu²⁺ after Br– leads to partial quenching at 608 nm with concomitant partial appearance of fluorescence emission around 485 nm. The mechanism was studied and confirmed. A logic gate is an idealized or physical device implementing a Boolean function，that is，it performs a logical operation on one or more logical inputs，and produces a single logical output. These structurally simple molecules can mimic the functionnalities of various complex logic gate such as EnYES，EnNOT，EnIMP，EnINH，EnNAND arrays by selection of inputs（nature of ions，sequence of additions and excitation wavelength）and outputs（fluorescence reading wavelength and threshold），1∶2 demultiplexer and keyboard.

Key words: fluorescence, complexation, ion recognition, logic gate, keypad lock