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Abstract Metal–organic frameworks (MOFs) define a solid‐state platform for developing artificial photosystems. Efficient anisotropic exciton migrations in these frameworks entail “antenna behavior” that can power up the distal interior reaction centers (RC), driving charge separation between donor‐acceptor pairs. Reminiscent of the natural light‐harvesting complex, such processes can achieve high quantum yield by exploiting the vast interior surface of the porous crystallites. It is important to understand the optimum positioning of the RC site relative to the anisotropic exciton migration path within these frameworks. The efficiency of such antenna behavior is probed here through Stern–Volmer (SV) type analysis with a series of node‐anchored redox quenchers, ferrocene‐carboxylate, ferrocene acetate, and dinitrobenzoate. Decoding various intrinsic processes, this work constructs a revised SV formalism in solid assembly that hosts ultrafast anisotropic exciton migration to account for the intrinsic exciton hopping rate from the extrinsic electron transfer rate, and the dimension of effective quenching. This transformative understanding can be applied to other relevant solid‐state assemblies. 

Abstract Metal ‒ organic frameworks (MOFs) are widely studied molecular assemblies that have demonstrated promise for a range of potential applications. Given the unique and well-established photophysical and electrochemical properties of porphyrins, porphyrin-based MOFs are emerging as promising candidates for energy harvesting and conversion applications. Here we discuss the physical properties of porphyrin-based MOFs, highlighting the evolution of various optical and electronic features as a function of their modular framework structures and compositional variations. 

Abstract Solid‐state artificial photosystems need precise control over their singlet or triplet excited states to enable desired photochemical transformations. While persistent triplets are often selected to drive chemical bond formation or spin‐specific photoreactions, singlets can allow for ambient applications. Among different heterogeneous systems, metal–organic frameworks (MOFs) offer a solution‐stable platform with many benefits, including large chemically accessible interior surfaces where excitons can be transferred from their original formation sites. Porphyrins demonstrate high intersystem crossing efficiency, with QY_ISC ≈ 80% for free‐base (FB) cores, which can be increased to about 92% for palladium‐metalated cores. This study shows that framework assembly prevents ISC in FB‐MOFs; whereas, ISC is enhanced in Pd‐MOFs compared to monomeric linkers. The MOF topology influences the excited state dynamics, resulting in short‐lived triplets withτ_0.5≲10 ps in microporous MOFs. This extensive control over QY_ISC(from 0 to approximately 100%) and triplet behavior through framework assembly offers new design principles for creating artificial photosystems that operate exclusively in their singlet or triplet states manifold.