Owing to its simplicity, ethylene, as the most abundant organic feedstock, only finds limited applications in fine chemical synthesis, resulting in molecules of modest complexity. Ethylene difunctionalization allows for the synthesis of much more complex chemicals, but it is rare and almost always relies on transition-metal catalysis. Herein, we report an unprecedented metal-free radical difunctionalization of ethylene through a functional group migration strategy. The use of sulfone-based bifunctional reagents enables straightforward access to a wide range of diheteroarylated compounds under mild conditions in a highly selective manner. The precise modulation of radical polarity and kinetic preference arising from intramolecular functional group migration guarantee the success of the cascade three-bond forming process in a controllable manner.