1,4-Dicarbonyl compounds are intriguing motifs and versatile precursors in numerous pharmaceutical molecules and bioactive natural compounds.D irect incorporation of two carbonyl groups into ad ouble bond at both ends is straightforward, but also challenging.Represented herein is the first example of 1,2-dicarbonylation of alkenes by photocatalysis.K ey to success is that N(n-Bu) 4+ not only associates with the alkylanion to avoid protonation, but also activates the a-keto acid to undergo electrophilic addition. The a-keto acid is employed both for acyl generation and electrophilic addition. By tuning the reductive and electrophilic ability of the acyl precursor,u nsymmetric 1,4-dicarbonylation is achieved for the first time.T his metal-free,r edox-neutral and regioselective 1,2-dicarbonylation of alkenes is executed by ap hotocatalyst for versatile substrates under extremely mild conditions and shows great potential in biomolecular and drug molecular derivatization.