In a large bowl, beat the sugar, oil, eggs and vanilla until well blended. Combine the flour, cocoa, salt, baking soda, cinnamon and baking powder; gradually beat into sugar mixture until blended. Stir in zucchini and, if desired, chocolate chips. Transfer to 2 greased 8x4-in. loaf pans.
Bake at 350° for 50-55 minutes or until a toothpick inserted in the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.