The frosty relationship between the United States and Iran has created a chill in many areas of scholarly endeavor. One resulting battle, over whether Iranian scholars can belong to the American Chemical Society, has been largely resolved. But a new imbroglio looms with the arrest of a prominent U.S.-Iranian scholar who was visiting Tehran. The American Chemical Society announced this month that it had reversed a decision to expel its members in Iran and will allow all 36 of them to rejoin. The society had said that having such members put it in violation of U.S. trade sanctions against Iran. The Iranian members will, however, be denied two benefits: the group's career-development services, and reduced-price admission to the society's twice-yearly national meetings.