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Trigonal planar M₃(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high‐impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M₃(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double‐deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore‐space‐partitioned MOFs called M₃M₆pacsmade from co‐assembly between M₃single‐deck trimer and M_3x2double‐deck trimer. Important factors were identified on this multi‐modular MOF platform to guide optimization of each module, which enables the phase selection of M₃M₆pacsby overcoming the formation of previously‐always‐observed same‐cluster phases. The newpacsmaterials exhibit high surface area and high uptake capacity for CO₂and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C₂H₂/CO₂and C₂H₂/C₂H₄. Furthermore, new M₃M₆pacsmaterials show electrocatalytic properties with high activity.

Isoreticular chemistry, which enables property optimization by changing compositions without changing topology, is a powerful synthetic strategy. One of the biggest challenges facing isoreticular chemistry is to extend it to ligands with strongly coordinating substituent groups such as unbound −COOH, because competitive interactions between such groups and metal ions can derail isoreticular chemistry. It is even more challenging to have an isoreticular series of carboxyl‐functionalized MOFs capable of encompassing chemically disparate metal ions. Here, with the simultaneous introduction of carboxyl functionalization and pore space partition, a family of carboxyl‐functionalized materials is developed in diverse compositions from homometallic Cr³⁺and Ni²⁺to heterometallic Co²⁺/V³⁺, Ni²⁺/V³⁺, Co²⁺/In³⁺, Co²⁺/Ni²⁺. Cr‐MOFs remain highly crystalline in boiling water. Unprecedentedly, one Cr‐MOF can withstand the treatment cycle with 10mNaOH and 12mHCl, allowing reversible inter‐conversion between unbound −COOH acid form and −COO⁻base form. These materials exhibit excellent sorption properties such as high uptake capacity for CO₂(100.2 cm³ g⁻¹) and hydrocarbon gases (e.g., 142.1 cm³ g⁻¹for C₂H₂, 110.5 cm³ g⁻¹for C₂H₄) at 1 bar and 298K, high benzene/cyclohexane selectivity (up to ≈40), and promising separation performance for gas mixtures such as C₂H₂/CO₂and C₂H₂/C₂H₄.

Currently, few porous vanadium metal‐organic frameworks (V‐MOFs) are known and even fewer are obtainable as single crystals, resulting in limited information on their structures and properties. Here this work demonstrates remarkable promise of V‐MOFs by presenting an extensible family of V‐MOFs with tailorable pore geometry and properties. The synthesis leverages inter‐modular synergy on a tri‐modular pore‐partitioned platform. New V‐MOFs show a broad range of structural features and sorption properties suitable for gas storage and separation applications for C₂H₂/CO₂, C₂H₆/C₂H₄, and C₃H₈/C₃H₆. Thec/aratio of the hexagonal cell, a measure of pore shape, is tunable from 0.612 to 1.258. Other tunable properties include pore size from 5.0 to 10.9 Å and surface area from 820 to 2964 m²g⁻¹. With C₂H₂/CO₂selectivity from 3.3 to 11 and high uptake capacity for C₂H₂from 65.2 to 182 cm³g⁻¹(298K, 1 bar), an efficient separation is confirmed by breakthrough experiments. The near‐record high uptake for C₂H₆(166.8 cm³g⁻¹) contributes to the promise for C₂H₆‐selective separation of C₂H₆/C₂H₄. The multi‐module pore expansion enables transition from C₃H₆‐selective to more desirable C₃H₈‐selective separation with extraordinarily high C₃H₈uptake (254.9 cm³g⁻¹) and high separation potential (1.25 mmol g⁻¹) for C₃H₈/C₃H₆(50:50 v/v) mixture.