In a large saucepan, cook sugar and water over medium heat until sugar is dissolved. Add cranberries and cherries. Bring to a boil. Cook uncovered, until cranberries begin to pop, about 6 minutes. Reduce heat; cook 20 minutes longer or until thickened. Pour into a serving dish. Cover and chill for at least 2 hours. Yield: 3-1/2 cups.