Lanthanide-based metal–organic frameworks (Ln-MOFs), as notable materials, are constructed by Ln³⁺ ions and organic ligands, or Ln³⁺ ions functionalizing non-Ln-MOFs, and exhibit promising applications in various fields. Over the past decades, quite a lot of investigations of Ln-MOFs have been carried out, and many good results have been obtained. Among these results, Ln-MOFs as luminescent probes for unique detection are gradually becoming a hot topic due to their fast and effective luminescent response for the targeted substance. In this perspective article, we discuss the construction of luminescent Ln-MOFs, their applications in possible detection mechanisms, and summarize some examples of Ln-MOFs as luminescent probes for sensing cations, anions and small molecules.

Two 24-nuclear lanthanide clusters, Gd₂₄ and Dy₂₄ were obtained and structurally characterized. Magnetic investigations reveal that Gd₂₄ exhibits the largest entropy change (−ΔS_m) of 46.12 J kg⁻¹ K⁻¹ for ΔH = 7 T in all reported molecular clusters, and single-molecule magnet behaviour is observed in Dy₂₄.

An Eu-MOF can selectively detect PO₄³⁻ and it represents the first example of regenerable MOF-based luminescent probes for detecting PO₄³⁻.