A new pyrene based highly sensitive and selective Al³⁺ sensor, pyrene-2-(pyridin-2-ylmethylsulfanyl)-ethylamine (PP), was found to exhibit a turn-on fluorescence enhancement (FE) as high as 7.4 fold with K_d (2.55 ± 0.10) × 10⁻⁴ M and n = 1. This probe binds reversibly with Al³⁺ in the presence of H₂EDTA²⁻, both under intra- and exctracellular conditions. LOD determined by 3σ methods was found to be 15 nM while LOQ = 52.8 nM. The tentative coordination environment in the Al³⁺–PP complex was delineated by DFT calculations both on the free ligand and complex. The TDDFT calculations reveal spectral features comparable to the experimental ones.