Directional Electron Flow in a Selenoviologen‐Based Tetracationic Cyclophane for Enhanced Visible‐Light‐Driven Hydrogen Evolution

Abstract Directional electron flow in the photocatalyst enables efficient charge separation, which is essential for efficient photocatalysis of H 2 production. Here, we report a novel class of tetracationic cyclophanes ( 7 ) incorporating bipyridine Pt(II) and selenoviologen. X‐ray single‐crystal structures reveal that 7 not only fixes the distances and spatial positions between its individual units but also exhibits a box‐like rigid electron‐deficient cavity. Moreover, host–guest recognition phenomena are observed between 7 and ferrocene, forming host–guest complexes with a 1 : 1 stoichiometry. 7 exhibits good redox properties, narrow energy gaps, and strong absorption in the visible range (370–500 nm) due to containing two selenoviologen (SeV 2+ ) units. Meanwhile, the femtosecond transient absorption (fs‐TA) reveals that 7 has stabilized dicationic biradical, efficient charge separation, and facilitates directional electron flow to achieve efficient electron transfer due to the formation of rigid cyclophane and electronic architecture. Then, 7 is applied to visible‐light‐driven hydrogen evolution with high hydrogen production (132 μmol), generation rate (11 μmol/h), turnover number (221), and apparent quantum yield (1.7 %), which provides a simplified and efficient photocatalytic strategy for solar energy conversion.