Transformation of carbon dioxide to high value‐added chemicals becomes a significant challenge for clean energy studies. Here a stable and conductive covalent organic framework was developed for electrocatalytic carbon dioxide reduction to carbon monoxide in aqueous solution. The cobalt(II) phthalocyanine catalysts are topologically connected via robust phenazine linkage into a two‐dimensional tetragonal framework that is stable under boiling water, acid, or base conditions. The 2D lattice enables full π conjugation along x and y directions as well as π conduction along the z axis across the π columns. With these structural features, the electrocatalytic framework exhibits a faradaic efficiency of 96 %, an exceptional turnover number up to 320 000, and a long‐term turnover frequency of 11 412 hour−1, which is a 32‐fold improvement over molecular catalyst. The combination of catalytic activity, selectivity, efficiency, and durability is desirable for clean energy production.

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The poor electrical conductivity of two‐dimensional (2D) crystalline frameworks greatly limits their utilization in optoelectronics and sensor technology. Herein, we describe a conductive metallophthalocyanine‐based NiPc‐CoTAA framework with cobalt(II) tetraaza[14]annulene linkages. The high conjugation across the whole network combined with densely stacked metallophthalocyanine units endows this material with high electrical conductivity, which can be greatly enhanced by doping with iodine. The NiPc‐CoTAA framework was also fabricated as thin films with different thicknesses from 100 to 1000 nm by the steam‐assisted conversion method. These films enabled the detection of low‐concentration gases and exhibited remarkable sensitivity and stability. This study indicates the enormous potential of metallophthalocyanine‐based conductive frameworks in advanced stand‐off chemical sensors and provides a general strategy through tailor‐make molecular design to develop sensitive and stable chemical sensors for the detection of low‐concentration gases.

A porphyrin-based two-dimensional (2D) covalent organic framework (COF) was developed by a C 4 + C 4 topological diagram. It was constructed by the condensation of zinc 5,10,15,20-tetra­(4-aminophenyl)­porphyrin (TAPP) and zinc 5,10,15,20-tetra­(4-formylphenyl)­porphyrin (TFPP) under typical solvothermal conditions, leading to the formation of a porphyrin-based TAPP–TFPP–COF with tetragonal micropores at a size of 1.8 nm. The resultant crystalline framework exhibited high crystallinity, excellent stability, and good porosity. Resulting from the specific π-unit stacking columnar structure and excellent organic semiconducting property of porphyrins, the TAPP–TFPP–COF shows many promising applications in optoelectronics. Notably, after doping with iodine, the conductivity of this TAPP–TFPP–COF can be greatly enhanced from 1.12 × 10–10 to 1.46 × 10–7 S cm–1. Furthermore, the nanometer-thick TAPP–TFPP–COF films were obtained using a liquid–air interface growth strategy. A spectroscopic detection device was constructed using COF thin films which displayed highly selective sensitivity toward the near infrared irradiation at 700 nm with an on–off ratio of up to 2.8 × 104. This value ranks as the highest among other COF-based and metal-organic-framework-based semiconducting materials under similar conditions. These results illustrated the enormous potential of 2D porphyrin COFs for future applications in optoelectronic devices and constituted an important step toward the development of new types of functional crystalline materials.

Zirconium-based metal–organic frameworks (Zr-MOFs) have aroused enormous interest owing to their superior stability, flexible structures, and intriguing functions. Precise control over their crystalline structures, including topological structures, porosity, composition, and conformation, constitutes an important challenge to realize the tailor-made functionalization. In this work, we developed a new Zr-MOF (PCN-625) with a csq topological net, which is similar to that of the well-known PCN-222 and NU-1000. However, the significant difference lies in the conformation of porphyrin rings, which are vertical to the pore surfaces rather than in parallel. The resulting PCN-625 exhibits two types of one-dimensional channels with concrete diameters of 2.03 and 0.43 nm. Furthermore, the vertical porphyrins together with shrunken pore sizes could limit the accessibility of substrates to active centers in the framework. On the basis of the structural characteristics, PCN-625­(Fe) can be utilized as an efficient heterogeneous catalyst for the size-selective [4 + 2] hetero-Diels–Alder cycloaddition reaction. Due to its high chemical stability, this catalyst can be repeatedly used over six times. This work demonstrates that Zr-MOFs can serve as tailor-made scaffolds with enhanced flexibility for target-oriented functions.