In 1-cup measuring cup, mix raspberry and rhubarb liquids. If necessary, add enough water to make 1 cup. In 2-quart saucepan, mix 1/2 cup sugar, 1/2 teaspoon cinnamon and the cornstarch; stir in reserved liquid. Cook over medium heat 4 to 5 minutes, stirring constantly, until thickened; remove from heat. Stir in raspberries and rhubarb. Spoon into baking dish.