A pyrene-based probe bearing benzothiazole ionophore (Py-BTZ) was synthesised as a "turn-on" fluorescent chemosensor for the detection of Fe3+ and Fe2+ ions in CH3CN : H2O (1 : 1, v/v) solvent mixes. The chemosensor showed optical as well as colorimetric changes towards Fe3+ and Fe2+ ions along with a remarkable enhancement in fluorescence emission. The detection limit of Py-BTZ towards Fe3+ and Fe2+ ions was found to be 2.61 μM and 2.06 μM, respectively. The binding of Py-BTZ with Fe3+ and Fe2+ was determined by using FT-IR experiments. Interestingly, Py-BTZ shows aggregation induced emission enhancement (AIEE) properties in polar solvent mixes such as CH3CN : H2O (1 : 1, v/v).