Preheat your oven to 350°F (175°C). Grease a 9×5 inch loaf pan and line it with parchment paper, leaving an overhang on the sides for easy removal.
In a large bowl, sift together the all-purpose flour, unsweetened cocoa powder, baking powder, baking soda, and salt. Set aside.
In a separate large mixing bowl, whisk together the granulated sugar, light brown sugar, and vegetable oil until well combined.
Add the eggs one at a time to the sugar and oil mixture, whisking well after each addition. Stir in the vanilla extract.
Alternately add the dry ingredients and the buttermilk to the wet ingredients, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.
Fold in the semi-sweet chocolate chips gently with a spatula.
Pour the batter into the prepared loaf pan and smooth the top with a spatula.
Bake in the preheated oven for 50 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs but no wet batter.
Remove the loaf from the oven and let it cool in the pan for 15 minutes.
Using the parchment paper overhang, lift the loaf out of the pan and transfer it to a wire rack to cool completely before slicing.