Mix the flour, sugar and butter or margarine. Press into the batter of a 13x9 inch ungreased baking pan. Bake at 350 degrees F (175 degrees C) for 15 minutes.
Mix the raspberries, orange juice, and cornstarch in a 1 quart sauce pan. Heat to boiling, stirring constantly. Boil and stir for 1 minute. Let cool for 10 minutes.
Sprinkle chocolate chips over baked crust and spoon the raspberry mixture over the top.
Bake at 350 degrees F (1715 degrees C) for 20 minutes or until the raspberry mixture has set. Remove from oven and let cool. Drizzle with additional melted chocolate if desired. Cut into 2x1 inch squares.