Preheat oven to 350F. Prepare a loaf pan by lining with parchment paper or nonstick spray. In a large bowl mix dry ingredients together with chocolate chunks. In another bowl whisk together sugar,eggs,vanilla, yogurt, oil & mashed banana. Mix until smooth.Add wet ingredients to dry ingredients and mix just until blended. Don't overmix. Add in Zucchini and mix until the Zucchini is dispersed evenly throughout the batter. Place batter into loaf pan and spread out evenly. Take chocolate chips and sprinkle over batter, press them in lightly with your hand.Bake for 45-50 minutes or until toothpick is inserted and comes out clean.