Tailoring Microstructure in Copper‐Based Conductive Metal–Organic Frameworks for Enhanced Chemiresistive Sensing and Uptake of Sulfur Dioxide

Abstract Crystal engineering of 2D, conductive metal–organic frameworks (2D cMOFs) offers a powerful strategy to tailor the physicochemical properties of these materials for electrochemical applications. However, achieving precise morphological control remains challenging due to limited understanding of their nucleation and growth mechanisms. This paper reports a precursor‐ and solvent‐mediated approach to modulate the microstructure, porosity, and conductivity of Cu 3 (HHTP) 2 (HHTP = 2,3,6,7,10,11‐hexahydroxytriphenylene), a model 2D cMOF. Varying the copper precursor identity in mixed aqueous–organic solvents generates four morphologically distinct, yet structurally analogous Cu 3 (HHTP) 2 particles with globular, aggregated, sheet‐like, and rod‐like shapes. These morphological variations impact the performance of Cu 3 (HHTP) 2 in SO 2 uptake and sensing. Gas uptake correlates with BET surface area, with globular crystals exhibiting the highest surface area (362 m 2 g −1 ) and SO 2 uptake (3.7 mmol g −1 ) under ambient conditions, while kinetic profiles reveal two mass‐transfer regimes corresponding to chemisorption followed by intraparticle diffusion. Conversely, SO 2 sensing scales inversely with particle aspect ratio, where aggregated particles (aspect ratio ≈0.99) achieve the highest sensitivity across 1–40 ppm SO 2 , with a detection limit of 80 parts‐per‐billion. These results establish a structure–property relationship in Cu 3 (HHTP) 2 and offer a generalizable strategy for optimizing 2D cMOFs for environmental and electronic applications.