Controlled Synthesis of High‐Nuclearity Th ₃₈ Cluster for Efficient Photocatalytic Dehydrogenative Cross‐Coupling

Actinide clusters represent a significant platform for decoding the complex chemical behavior of actinide elements, providing significant insights for the development of nuclear reactors and the management of radioactive waste. However, compared to other metal clusters, actinide clusters are still underexplored, especially high‐nuclearity thorium clusters. Here, we developed a synthetic strategy, in the form of “cluster from cluster” to construct the highest nuclearity thorium cluster ( Th 38 ) so far. It exhibits remarkable stability under high γ‐ray irradiation (up to 690 kGy) and displays unprecedented dispersibility and stability under strong acid conditions (pH = 1). Moreover, the high stability and unique electronic structure of Th 38 renders it an excellent catalyst for the photocatalytic synthesis of 4‐quinazolinones. This work utilizes a strategy to achieve the selfassembly of the highest nuclearity Th 38 and expands its potential applications.