Multi‐Light‐Responsive Upconversion‐and‐Downshifting‐Based Circularly Polarized Luminescent Switches in Chiral Metal–Organic Frameworks

Abstract Metal–organic frameworks (MOFs) have attracted tremendous attention for several novel applications. However, functional MOFs with light‐responsive circularly polarized luminescence (CPL) are not examined in detail. Therefore, a dual CPL switch exhibiting both upconversion (UC) and downshifting (DS) CPL in the solid state is constructed by loading a luminescent diarylethene derivative (DAEC) and UC nanoparticles (UCNPs) into chiral MOFs. The chiral MOF⊃DAEC composites exhibit both photoswitchable luminescence and DS‐CPL properties under alternating UV and visible light irradiation. Additionally, a reversible UC‐CPL switch is realized using near‐infrared (NIR) and visible light irradiation by introducing energy‐level‐matched UCNPs and DAEC into the chiral MOFs. The dissymmetry factor ( g lum ) of UC‐CPL is noted to be significantly amplified through energy transfer compared to that of DS‐CPL, which indicates that the information on circular polarization can be manipulated by altering the incident light. A chiroptical logic circuit with a 2D information output is designed with UV, visible, and NIR light as inputs by setting a rational threshold.