We report a novel indium(III) chloride complex that exhibits aggregation-induced emission (AIE) and functions as a selective turn-off fluorescent chemosensor for perfluoroalkyl substances (PFAS). The complex shows strong blue-shifted luminescence quenching upon interaction with perfluoroheptanoic acid (PFHpA) and perfluorooctanoic acid (PFOA) due to stabilization of the ground state molecular orbitals relative to those of the excited state. The selectivity of these compounds for PFOA and PFHpA is also reflected in the dipole moment and thus emission intensity of this complex, hence, they represent promising platforms for sensing "forever chemicals".