Preheat your oven to 350°F.
Grease a 9x5-inch loaf pan or line it with parchment paper.
Grate the zucchini and lightly blot excess moisture with a paper towel. Do not squeeze it completely dry.
In a large bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt.
In a separate bowl, whisk the eggs, oil, brown sugar, granulated sugar, and vanilla until smooth.
Stir the wet ingredients into the dry ingredients until just combined.
Fold in the grated zucchini and chocolate chips. The batter will be thick.
Spread the batter evenly into the prepared loaf pan and sprinkle a few extra chocolate chips on top if desired.
Bake for 50 to 60 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.
Allow the bread to cool in the pan for 15 minutes before transferring to a wire rack to cool completely.