Polyoxometalate-based one-dimensional subnanomaterials

One-dimensional (1D) subnanomaterials (SNMs), including subnanowires (SNWs) and subnanobelts (SNBs), have diameters or thicknesses comparable to the unit cell size and exhibit polymer-like properties, such as rheology, gelling, and adhesion, owing to their dimensional similarity to polymer chains. Originally, single-component 1D SNMs were dominant, but the development of the cluster-nuclei coassembly (CNCA) strategy has enabled the fabrication of various polyoxometalate (POM)-based 1D SNMs with precisely controlled compositions and structures. In this review, a variety of SNWs and SNBs, including POM, metal cluster-POM, metal cation-POM, metal oxide-POM, metal sulfide-POM, and high-entropy oxide-POM materials, are discussed, paying particular attention to their synthesis, programmable structures, polymer‐like properties, and excellent performance in gelling, adhesion, catalysis, polarization, and photothermal conversion applications. Moreover, the outstanding processability of 1D SNMs, which enables the construction of macroscale assemblies with expanded applicability, such as fibers, films, and gels, is described. Finally, challenges and future directions are discussed, providing new viewpoints on the development and applications of POM-based 1D SNMs.