Defect‐Engineered Dual‐Functional UiO‐67 Type Framework: Ultra‐Sensitive Ratiometric Fluorescence Sensing of Spectinomycin and Long‐Lived Room‐Temperature Phosphorescence for Anti‐Counterfeiting

ABSTRACT Spectinomycin (SPT) lacks native chromophores and exhibits only weak far‐ ultraviolet absorption, rendering its sensitive and selective detection highly challenging via conventional optical methods. Herein, we report a dual‐functional optical platform based on a UiO‐67 framework with missing‐linker defects constructed through mixed‐linker doping of H 3 bptc. After pore‐confined loading of Nile blue (NB), the resultant NB@UiO‐67‐bptc functions as a ratiometric fluorescent sensor for SPT, driven by SPT‐induced NB excimer formation within the confined pore environment. The sensor delivers an ultra‐low detection limit of 3.7 nM, an ultrafast response within 5 s, and a distinctive capability to discriminate SPT from other structurally analogous aminoglycoside antibiotics. The defective MOF carries abundant uncoordinated carboxyl groups, which can form hydrogen‐bonding with sodium alginate (SA). The resulting composite film (UiO‐67‐bptc@SA) emits bright cyan long‐afterglow film with an average phosphorescence lifetime of 759.8 ms and a naked‐eye‐visible afterglow of up to 2 s. This work demonstrates that a single defect‐engineering modification can integrate two heterogeneous optical functions into one MOF system, providing a straightforward strategy for constructing multifunctional MOF optical materials for sensing and anti‐counterfeiting applications.