Prepare the oven and pan: Preheat your oven to 375 F degrees. Spray a loaf pan generously with cooking spray or grease it with butter.
Mix the dry ingredients: In a large bowl combine the flour, baking powder, baking soda, cinnamon, cocoa powder and salt.
Prepare the zucchini: Grate the zucchini using a cheese grater. Place the shredded zucchini in a strainer, cheese cloth, or in a paper towel. Squeeze the excess moisture out. You should be left with about 1 cup of shredded zucchini.
Mix the wet ingredients: In a separate bowl, mix the shredded zucchini, oil, yogurt, egg and whisk well. Add in the sugar and mix until it begins to dissolve.
Mix everything together: Add the dry ingredients to the wet ingredients and mix using a rubber spatula. Stir in the chocolate chips using a spatula.
Bake the loaf: Transfer the batter into the prepared loaf pan and place in the oven. Bake for 45 minutes to 1 hour, or until an inserted toothpick comes out clean. Let it cool in the loaf pan for about 10 minutes then transfer it to a cooling rack or on a cutting board.
Slice and serve.