We report a 2-(4-amino-2-hydroxyphenyl)benzothiazole based Schiff-base, a potential excited state intramolecular proton transfer (ESIPT) chromophore, exhibits aggregation induced emission enhancement (AIEE) in the solvent mixture of DMSO:HB. The presence of Cu2+ ions promote imine hydrolysis resulting the formation of Cu2+ complex of 2-(4-amino-2-hydroxyphenyl)benzothiazole, with the consequent cessation of the emission process leading to “turn-off” detection of Cu2+. The introduction of PO43− ions revived fluorescence emission through decomplexation of the putative Cu2+ complex, thereby releasing 2-(4-amino-2-hydroxyphenyl)benzothiazole in the solution. Additionally, we have successfully demonstrated the practical application of the probe by developing the portable sensor paper strips.