Preheat the oven to 350°F (175°C). Grease a 9×13 inch sheet pan and line with parchment paper, leaving an overhang on two sides for easy removal.
In a large mixing bowl, whisk together the granulated sugar, brown sugar, and vegetable oil until well combined.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
Fold in the shredded zucchini until evenly distributed.
In a separate bowl, sift together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, folding gently until just combined. Do not overmix.
Fold in the semi-sweet chocolate chips.
Pour the batter into the prepared sheet pan and spread it evenly with a spatula.
Bake for 28-32 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs but no wet batter.
Remove from the oven and let cool completely in the pan on a wire rack.
Once cooled, use the parchment paper overhang to lift the brownies out of the pan and cut into 16 squares.