Noncovalent interactions play fundamental roles in many organic and biochemical processes, including hydrogen and halogen bonding, which are vital in the fields of synthesis and catalysis. Herein, we describe the application of halogen bonding interactions to facilitate the reaction balance between an electron donor–acceptor (EDA) complex and Ph2Se2 for the synthesis of a series of organoselenium compounds. The EDA complex concept has recently emerged as an attractive path for visible light-induced transformations due to facile reaction conditions and the avoidance of photocatalysts. Density functional theory calculations reveal that an iodine–π* interaction leads to the formation of an alkyl radical from the N-(acyloxy)phthalimide ester. The resulting alkyl radical is captured by the diselenide–I• complex to form the C–Se bond. The developed selenide synthesis strategy has been applied in the transformation of primary, secondary, and tertiary carboxylic acids as well as a series of natural products, drugs, and α-selenoamino acids.