A new visible-light photocatalytic multicomponent reaction (MCR) involving N-alkyl-N-methylanilines, N-isocyanoiminotriphenylphosphorane, and carboxylic acids leading to 1,3,4-oxadiazole derivatives is reported. The developed mild reaction conditions enable a broad substrate scope and good functional group tolerance, as further highlighted in the late-stage functionalization of amino acids and drugs. Additionally, a two-step one-pot protocol for the synthesis of non-symmetrical diacylhydrazines is also reported.