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This paper describes the demonstration of a series of heterobimetallic, isoreticular 2D conductive metal–organic frameworks (MOFs) with metallophthalocyanine (MPc, M=Co and Ni) units interconnected by Cu nodes towards low-power chemiresistive sensing of ppm-levels of carbon monoxide (CO). Devices achieve sub-part-per-million (ppm) limits of detection (LOD) of 0.53 ppm toward CO at low driving voltages of 0.1 V. MPc-based Cu-linked MOFs can continuously detect CO at 50 ppm, the permissible exposure limit required by Occupational Health and Safety Assessment Series, for multiple exposures and realize CO detection in air and humid environment. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), density functional theory (DFT) calculations, and comparison experiments suggest the contribution of Cu nodes for CO binding and the essential role of MPc units in tuning and amplifying the sensing response. 

Abstract Polymeric supramolecular hydrogels (PSHs) leverage the thermodynamic and kinetic properties of non‐covalent interactions between polymer chains to govern their structural characteristics. As these materials are formed via endothermic or exothermic equilibria, their thermal response is challenging to control without drastically changing the nature of the chemistry used to join them. In this study, we introduce a novel class of PSHs utilizing the intercalation of double‐stranded DNA (dsDNA) as the primary dynamic non‐covalent interaction. The resulting dsDNA intercalating supramolecular hydrogels (DISHs) can be tuned to exhibit both endothermically or exothermically driven binding through strategic selection of intercalators. Bifunctional polyethylene glycol (M_W~2000 Da) capped with intercalators of varying hydrophobicity, charge, and size (acridine, psoralen, thiazole orange, and phenanthridine) produced DISHs with comparable moduli (500–1000 Pa), but unique thermal viscoelastic responses. Notably, acridine‐based cross‐linkers displayed invariant and even increasing relaxation times with temperature, suggesting an endothermic binding mechanism. This methodology expands the set of structure‐properties available to biomass‐derived DNA biomaterials and promises a new material system where a broad set of thermal and viscoelastic responses can be obtained due to the sheer number and variety of intercalating molecules.