Luminescent Metal–Organic Frameworks (MOFs) as a Chemopalette: Tuning the Thermochromic Behavior of Dual‐Emissive Phosphorescence by Adjusting the Supramolecular Microenvironments

Abstract Two classical copper(I)‐cluster‐based luminophores, namely, Cu 4 I 4 and [Cu 3 Pz 3 ] 2 (Pz=pyrazolate), are immobilized in a supramolecular system through the formation of metal–organic framework (MOF) materials. This series of luminescent MOF materials, namely, [Cu 4 I 4 (NH 3 )Cu 3 ( L1 ) 3 ] n , [Cu 4 I 4 (NH 2 CH 3 )Cu 3 ( L1 ) 3 ] n , and [Cu 4 I 4 Cu 3 ( L2 ) 3 ] n ( L1 =3‐(4‐pyridyl)‐5‐( p ‐tolyl)pyrazolate; L2 =3‐(4‐pyridyl)‐5‐(2,4‐dimethylphenyl)pyrazolate), exhibit diverse thermochromism attributed to the relative functioning efficacy of the two coordination luminophores. Such an intriguing chemopalette effect is regulated by the different supramolecular microenvironments between the two‐dimensional layers of these MOFs, and in particular, by the fine‐tuned Cu–Cu distances in the excimeric [Cu 3 Pz 3 ] 2 luminophore. The structure–property elucidation of the thermochromic behavior allows one to understand these optical materials with unusual dual‐emissive properties.