Preheat the oven to 350°F (176°C).
Shred the zucchini and set aside (do not squeeze the shredded zucchini).
In a large bowl; combine eggs, brown sugar, vanilla extract, oil and mix well.
Place a sifter or fine mesh on top of the bowl. Add flour, cocoa, baking soda, baking powder, salt and sift. Mix until combined.
Add shredded zucchini and gently fold into the batter.
Add chocolate chips and fold into the batter.
Spray cooking butter/oil in loaf pan. Transfer the batter to the loaf pan.
Bake for 55 minutes or until a toothpick placed in the center of the bread comes out clean.
Remove from the oven and rest the bread in the pan for 10 minutes.
Remove the bread from the loaf pan and transfer to a cake rack.