Preheat oven to 350°F (175°C). Grease and flour a 9x5 inch loaf pan or line with parchment paper.

In a large mixing bowl, combine eggs, sugar, oil, and vanilla.

Beat with an electric mixer on low speed for about 1 1/2 minutes until well blended.

Add grated zucchini and melted, cooled chocolate; stir to blend.

In a separate bowl, sift together flour, baking soda, salt, and cinnamon.

Add dry ingredients, chocolate chips, and chopped walnuts to the egg mixture.

Stir just enough to blend in the dry ingredients; do not overmix.

Pour batter into the prepared loaf pan.

Bake at 350°F (175°C) for 60 to 70 minutes, or until a wooden pick inserted in the center comes out clean.

Cool in the pan on a wire rack for 10 minutes.

Turn out of the pan and cool completely on the rack before slicing.