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.　©　2016　Elsevier　B.V.　All　rights　reserved.