Metal-catalyzed halogenation of the C-H bond and decarbonylation of aldehyde are conventionally done in nature. However, metal-mediated decarbonylative halogenation is unknown. We have developed the first metal-mediated decarbonylative halogenation reaction starting from the divanadium oxoperoxo complex K3V25+(O-2(2-))(4)(O2-)(2)(mu-OH) (1). A concerted decarbonylative halogenation reaction was proposed based on experimental observations.