Recent advances on <scp>MOF</scp> ‐based colorimetric sensors

Abstract Metal–organic frameworks (MOFs) have emerged as promising platforms for colorimetric sensing due to their tunable structures, high porosity, and ability to support diverse optical responses. Among various sensing technologies, colorimetric sensing stands out for its simplicity, cost‐effectiveness, and visual interpretability, making it especially suitable for point‐of‐need applications. This review highlights recent advances in MOF‐based colorimetric sensors, with a particular focus on the mechanisms by which analyte‐induced signals are transduced into visible color changes. We classify these sensing systems into three mechanistic categories: (i) direct chromogenic responses arising from interactions between analytes and intrinsic or modified MOF components; (ii) structural or refractive index changes in the MOF framework itself; and (iii) MOF‐mediated external chromogenic reactions, in which the MOF acts as a catalyst or host. Representative examples for each category are discussed, along with data acquisition methods and strategies for signal analysis. By emphasizing the mechanistic underpinnings of color generation, this review aims to provide a framework for the rational design of MOF‐based sensors. Key challenges and future opportunities are also discussed, including enhancing selectivity, environmental robustness, and single‐sensor multiplexing capabilities.