A mechanochemical and solvent/catalyst-free functionalization of olefins with hypervalent iodine reagents has been developed, enabling the synthesis of 1,3-dioxygenated compounds. Under similar reaction conditions with the addition of molecular iodine, 1,4iodoalcohols can be synthesized. These valuable products are non-trivial to achieve via standard solutionphase methods. Mechanistic study reveals that the hypervalent iodine reagent might dimerize at solid state with the help of mechanical force. The active monomeric form of hypervalent iodine reagent might trigger the 1,3and 1,4-difunctionalization reactions in an intermolecular cascade manner.