Lacunary Evolution of Molybdenum Blue Clusters for Efficient and Sustainable Photocatalytic Chemodivergent C─C Coupling Reactions

High‐nuclearity molybdenum blue (MB) clusters with regular lacunary variation are of great importance for polyoxometalate structure evolution and photocatalytic application study, but their synthesis still remains a huge challenge. Herein, we successfully synthesized a series of high‐nuclearity MB clusters, S 2 Mo 62 , SMo 53 W 7 , Mo 50 W 8 , and Mo 44 W 8 , which exhibit regular lacunary variation. More importantly, such structural variation endows these MB clusters with distinct Lewis acidity and redox properties. Consequently, when employed as heterogeneous photocatalysts for the chemodivergent C─C coupling reactions between 1,3‐diketones and alkenes, the hexa‐lacunary Mo 50 W 8 and Mo 44 W 8 with more Lewis acid sites can achieve a 93% 1,5‐diketone yield within 12 h, while parent S 2 Mo 62 with superior oxygen activation can achieve a 99% 1,4‐diketone yield within 3 h. Furthermore, Mo 50 W 8 enables gram‐scale and sunlight driven synthesis of diverse 1,5‐diketone, and maintains long‐term cycling stability over 370 h (16 cycles). This work represents the first report of high‐nuclearity MB clusters with regular lacunary variation, and extends their application to sunlight driven photocatalytic C─C coupling reaction, highlighting the innovative research of MB clusters.