The consecutive photo-induced electron-transfer (conPET) process found with perylene diimide (PDI) overcomes the limitation of visible-light photocatalysis and sheds light on effective solar energy conversion. By the incorporation of PDI into a metal-organic polymer Zn-PDI, a heterogeneous approach was achieved to tackle the poor solubility and strong tendency to aggregate of PDIs that restricted the exploitation of this outstanding homogeneous process. The interplay between metal-PDI coordination and π···π stacking of the organized PDI arrays in Zn-PDI facilitates the conPET process for the visible light-driven reduction of aryl halides by stabilizing the radical-anion intermediate and catalyst-substrate interacted moiety. These synergistic effects between the PDI arrays and Zn sites further render Zn-PDI photoactivity for fundamental oxidation of benzyl alcohols and amines. The tunable and modular nature of the two-dimensional metal-organic polymers makes the catalyst-embedding strategy promising for the development of ideal photocatalysts toward the better utilization of solar energy.

A major challenge is the development of multifunctional metal-organic frameworks (MOFs), wherein magnetic and electronic functionality can be controlled simultaneously. Herein, we rationally construct two 3D MOFs by introducing the redox active ligand tetra(4-pyridyl)tetrathiafulvalene (TTF(py) ) and spin-crossover Fe centers. The materials exhibit redox activity, in addition to thermally and photo-induced spin crossover (SCO). A crystal-to-crystal transformation induced by I doping has also been observed and the resulting intercalated structure determined. The conductivity could be significantly enhanced (up to 3 orders of magnitude) by modulating the electronic state of the framework via oxidative doping; SCO behavior was also modified and the photo-magnetic behavior was switched off. This work provides a new strategy to tune the spin state and conductivity of framework materials through guest-induced redox-state switching.