MgI2-catalyzed nucleophilic ring-opening reactions of donor-acceptor cyclopropanes with indoline-2-thiones as easy-to-handle sulfur nucleophiles were investigated. A series of functionalized γ-indolylthio butyric acid derivatives were synthesized in good to excellent yields under mild reaction conditions. Furthermore, the thioether functionalized ring-opening products could be transformed to sulfone and methionine analogues.