A　near-infrared　fluorescent　chemosensor　based　on　squaraine　has　been　synthesized,　and　its　cascade　recognition　for　copper　ion,　biological　phosphate　PPi,　and　amino　acids　has　also　been　investigated　by　spectroscopic　techniques.　SQ-1　exhibits　high　selectivity　and　sensitivity　for　sensing　Cu2+　over　other　metal　ions　by　reversibly　forming　a　[SQ-1-Cu2+]　complex.　By　tandem　ligand　exchange,　PPi　and　amino　acids　can　remove　Cu2+　from　the　complex　and　restore　the　spectral　signal　of　SQ-1,　which　can　be　used　for　cascade　recognition　of　these　biologically　active　species.　Notably,　an　IMPLICATION　logic　gate　can　be　constructed　based　on　this　bifunctional　chemosensing　system.　(C)　2016　Elsevier　B.V.　All　rights　reserved.