Preheat the oven to 350°F. Spray two 8x4-inch loaf pans with nonstick spray.
In a large bowl, use an electric mixer to beat the sugar, oil, eggs and vanilla until well-mixed.
In a separate bowl, whisk together the flour, cocoa powder, salt, baking soda and baking powder. Gradually beat the sugar mixture until blended. Stir in the zucchini and the chocolate chips.
Bake 50 to 55 minutes, or until a toothpick inserted into the center comes out clean. Cool for 10 minutes before removing the loaves from the pans to cool completely.