Two chiral and one racemic fluorescent dimeric zinc complex {[Zn₂(slysH)₂Cl₂]·(CH₃OH)₂·(H₂O)₃ (1), [Zn₂(slysH)₂ (NO₃)₂]·(H₂O)₃ (2), [Zn₂(rslysH)₂(μ-OAc)₂] (3)} are compared herein. Presently, 3 has been synthesized by a one-pot reaction in which the D-/L- lysine-based Schiff base ligand [slys = 6-amino-2-{(2-hydroxybenzylidene)amino}hexanoate] is generated in situ. These compounds have been characterized by single-crystal X-ray diffraction and by various spectroscopic techniques. The structures of previously reported compounds 1 and 2 are closely related in which two zinc centers possess two phenolate-bridges and an axial chloride or nitrate ligand. The novel compound 3 differs structurally through the presence and coordination mode of two bridging acetate groups spanning the dizinc core and formally releasing the phenolate bridging Schiff base ligands. These compounds (1–3) are highly blue fluorescent, either as solids or dissolved species. Under neutral and aqueous conditions (pH 7.4; 0.01 M HEPES buffer, H₂O–MeOH = 9 : 1), the quantum yields are Φ_F = 0.17 (1), 0.21 (2) (λ_ex = 352 nm, λ_em = 452 nm), Φ_F = 0.16 (3) (λ_ex = 354 nm, λ_em = 452 nm). Complex 3 metal ion detection capability (i.e., Na⁺, K⁺, Ca²⁺, Mg²⁺, Co²⁺, Ni²⁺, Mn²⁺, Cu²⁺, Pb²⁺, Ag⁺, Hg²⁺, and Cd²⁺) was gauged in aqueous media at physiological pH facilitated by the similarity of its starting photophysical properties with those of 1 and 2. These dizinc species were all found to act as a highly selective fluorescent ON–OFF probes for Cu²⁺ through the direct displacement of two zinc ions in aqueous media at physiological pH range. The phenolate-bridged compounds 1 and 2, however, showed better selectivity towards Cu²⁺ over competitive ions, Ni²⁺ and Co²⁺ than the acetate-bridged compound 3.