Preheat oven to 325 degrees F and grease a 9" x 5" loaf pan.In a microwave safe bowl soften the butter then stir in the sugar and combine well. Add the eggs and vanilla extract, stirring to combine well again.In a separate bowl whisk together the flour, cocoa powder, baking powder, baking soda and salt.Add the dry ingredients to the wet ingredients and stir until combined.Stir in the zucchini and chocolate chips. Pour the batter into a greased loaf pan and sprinkle with a few more chocolate chips.Bake at 325 degrees for 60-75 minutes (1 hour - 1 hour & 15 minutes).Allow the bread to set in the bread pan at least 30 minutes, so the bottom doesn’t stick when removing.