Wells-Dawson polyoxometalates (WD POMs) are an important subgroup within the diverse family of POMs. In the last two decades, there has been remarkable progress in the structure modification and post-functionalization of WD POMs, which has unlocked their enormous potential across various domains, including energy materials, catalysis (photocatalysis, electrocatalysis), functional materials (sensors, optical materials, electrochromic materials, magnetic materials) or biology/medicine (anticancer and antibacterial activities). What makes these systems particularly captivating is their highly adaptable topological structure, combined with the versatile functionalization methods and consequently their precise design and control, which transfers into a wide range of applications. In our comprehensive review, we focus on the exploration of their intricate structural characteristics which play a pivotal role in their functional properties. Moreover, the exciting and promising applications of WD POMs across various areas of science disciplines are highlighted. Our aim is to shed light on the current state of the art, identify emerging trends, and provide insights into the potential future directions of WD POM research, which are still being expanded, especially given the rapid development and continuous progress in the design of novel WD POM subunit functionalities. By doing so, we hope to contribute to a better understanding of these remarkable materials and inspire further innovation in their utilization.

This work was supported by the National Science Centre, Poland (grant numbers UMO-2022/45/N/ST4/00632 (D.N.), UMO-2020/39/D/ST4/01182 (A.G.), UMO-2022/44/C/ST4/00017 (E.W-S.), 2022/47/B/ST4/02310 (V.P.)). Daria Nowicka is a scholarship holder of the Adam Mickiewicz University in Poznan Foundation for the 2023/2024 academic year. Adam Gorczyński is a scholarship holder of the Polish Ministry of Education and Science for outstanding young scientists.