Preheat oven to 350 degrees F (175 degrees C). Lightly grease two 9×5 inch loaf pans. In a microwave-safe bowl, microwave chocolate until melted. Stir occasionally until chocolate is smooth.
In a large bowl, combine eggs, sugar, oil, grated zucchini, vanilla and chocolate; beat well. Stir in the flour baking soda, salt and cinnamon. Fold in the chocolate chips. Pour batter into prepared loaf pans.
Bake in preheated oven for 60 to 70 minutes, or until a toothpick inserted into the center of a loaf comes out clean.