Preheat oven to 350°F, grease a 9x5-inch loaf pan with baking spray.
Grate zucchini. I like to leave the grated zucchini in collander so it can drain while mixing the other ingredients. Or you can just lightly press the extra liquid before adding the zucchini.
Whisk together the flour, unsweetened cocoa, baking soda, salt, and cinnamon in a large bowl. Whisk until there the ingredients are well combined.
In a separate large bowl, beat together the sugar and eggs until smooth. Add the melted butter, instant coffee granules, and vanilla extract and beat until smooth.
Add the shredded zucchini into the sugar egg mixture. Then add the flour to the zucchini mixture in small additions, stirring to combine after each addition.
Pour batter into greased pan. Place into the oven. Bake for 50 minutes at 350°F, or until a skewer inserted into the center comes out clean and easily. Let cool in the pan for 5 minutes. Remove from the loaf pans and let cool completely on a rack.