A highly efficient noble-metal-free homogeneous system for a cross-coupling hydrogen evolution (CCHE) reaction is developed. With cheap, earth-abundant eosin Y and molecular catalyst Co(dmgH)2Cl2, good to excellent yields for coupling reactions with a variety of isoquinolines and indole substrates and H2 have been achieved without any sacrificial oxidants. Mechanistic insights provide rich information on the effective, clean, and economic CCHE reaction.

Although natural sunlight-mediated photocatalysis is a clean, efficient, and green approach to access organic products, its application in the synthesis of covalent organic frameworks (COFs), however, is still unprecedented. Herein, we first report the sunlight photocatalytic synthesis of COF under ambient conditions. Furthermore, this “window ledge” reaction generated benzoxazole-linked COF is stable and can be applied as a reusable photocatalyst to highly promote visible-light-driven aerobic oxidation of sulfides to sulfoxides. These results not only enrich the COF synthetic methodology but also open a new route to access COFs in a green and sustainable way.

By using catalytic amount of CoCl2 with dmgH (dimethylglyoxime) as ligand to form a photosensitizer in situ, a highly selective, efficient, and environmentally benign visible light mediated cross-dehydrogenative coupling (CDC) reaction has been developed in aqueous medium. The desired cross-coupling C-C bonds that involve Csp3 with Csp, Csp2, and Csp3, respectively, were achieved exclusively in high yields without formation of any other byproduct.