A new fluorescent zinc (II) complex‐based probe 1 encompassing a Schiff's base (E)‐2‐methoxy‐6‐((2‐[5‐nitropyridin‐2‐ylamino]ethylimino)methyl)phenol (HL) was designed, synthesized, and used for the highly selective detection of Cu2+. Ligand HL and complex 1 were characterized using various spectroscopic techniques such as 1H, 13C‐NMR, and FTIR spectroscopy, high‐resolution mass spectronomy (HRMS), UV/visible light spectroscopy, and fluorescence studies. Ligand HL did not exhibit any considerable change in fluorescence in the presence of various cations. Notably, its Zn(II) complex 1 exhibited highly selective ‘TURN‐OFF’ fluorescence signalling towards Cu2+ that remained uninterrupted with competing analytes. Probe 1 interacted with Cu2+ in 1:2 (1:Cu2+) stoichiometry as estimated through a Job's plot. Moreover, the selectivity of 1 was further confirmed through the interaction of the 1 + Cu2+ complex with some possible interfering metal ions inducing an insignificant response. Additionally, the association and quenching constant were determined to be 3.30 × 104 M−1 and 0.21 × 105 M−1 through the Benesi–Hildebrand method and Stern–Volmer plot, respectively.