The reaction of the tetravalent uranium [U(IV)] with dimethyldioxirane (DMD) in strongly acidic water-acetone solutions is accompanied by chemiluminescence (CL) in the visible (Vis) and infra-red (IR) regions. At least three independent reaction pathways are involved in the U(IV)-DMD oxidation: the first entails the non-chemiluminescent oxidation of U(IV) to the uranyl ion (UO(2) (2+)); the second involves the catalytic decomposition of DMD by U(IV) to afford singlet oxygen, as manifested by its characteristic IR-CL; and in the third process, slow Vis-CL (510-540 nm) is emitted, following DMD consumption.