Directional‐Polarity Engineering in Bithiophene‐Based Covalent Organic Frameworks Enables Selective Electron‐Transfer‐Mediated 1 O 2 Photocatalysis for Coupled H 2 O 2 Production and Furfuryl Alcohol Upgrading

ABSTRACT Selective photocatalytic generation of 1 O 2 through electron‐transfer pathways represents an attractive alternative to conventional triplet‐sensitized photooxygenation, yet remains limited by uncontrolled oxygen activation and poor reactive oxygen species (ROS) selectivity. Herein, we report a directional‐polarity engineering strategy that programs charge kinetics and interfacial‐O 2 activation in bithiophene‐based covalent organic frameworks (COFs) for selective O 2 →•O 2 − → 1 O 2 conversion. Systematic modulation of donor–acceptor polarity identifies a highly polarized bithiophene‐imine‐triazine framework that lowers exciton binding energy, accelerates ultrafast charge separation, and establishes directional electron transfer from bithiophene to adsorbed O 2 . Mechanistic studies reveal that this polarized framework thermodynamically promotes O 2 activation to •O 2 − via a bithiophene‐superoxide‐mediated pathway, followed by hole‐driven oxidation of •O 2 − at the adjacent phenylene units to generate 1 O 2 . 18 O 2 /H 2 18 O isotope‐labeling experiments and theoretical calculations reveal that 1 O 2 ‐mediated Achmatowicz rearrangements are dominated by non‐exchange pathways, together with minor favorable water‐mediated oxygen‐exchange pathways responsible for the observed oxygen scrambling during coupling furfuryl‐alcohol oxidation and H 2 O 2 formation. The optimized COFs achieve 1 O 2 generation rates of 769.6 µmol L −1 min −1 and H 2 O 2 productivity of 52.7 mmol g −1 h −1 while enabling near‐quantitative furfuryl‐alcohol upgrading under ambient conditions. This work establishes directional‐polarity engineering as a molecular strategy for steering electron‐transfer oxygen activation and selective ROS photocatalysis in crystalline organic semiconductors.