Preheat the oven to 350 degrees. Grease the bottom and sides of a 9x5 loaf pan and set aside.

In a medium mixing bowl, add the melted butter and brown sugar. Stir until well combined, about 2 minutes.

Add the eggs and vanilla and mix well to combine.

Add the flour, cocoa, baking soda, baking powder, and salt. Mix until just combined.

Add the shredded zucchini and chocolate chips and stir until just incorporated.

Add the batter to the bread pan and smooth the top with a spatula.

Bake the bread until a toothpick inserted into the center comes out clean, about 1 hour.

Let the bread cool in the pan for 10 minutes and then run a butter knife along the edges. Remove from the pan and let cool on a wire rack.

Serve warm or at room temperature. Store leftovers in an air-tight container.