Preheat oven to 350°F and line two muffin tins with cupcake liners (or spray the cups generously with cooking spray). Using a stand mixer fitted with the paddle attachment (or a large mixing bowl with a hand mixer), combine the oil, sugar, brown sugar, eggs and vanilla and beat until creamy.
In a separate bowl, combine the flour, cocoa, baking powder, baking soda, salt and cinnamon. Mix well. Gradually add to the butter mixture and beat on medium-low speed until just combined. Fold in the zucchini and chocolate chips.
Divide the batter between the prepared muffins cups. The batter will be thick and the cups should be 3/4 of the way full. Bake in the preheated oven for 20 minutes, or until a toothpick inserted into the centers comes out clean. Serve warm!