Preheat oven to 350 degrees F.
In a large bowl, combine flour, sugars, cocoa powder, baking powder, baking soda and salt. Mix well to combine.
In a separate bowl, combine butter, eggs, bananas, pumpkin puree, Greek yogurt and vanilla extra. Mix with electric mixer to fully combine.
Combine wet ingredients and dry ingredients, along with chocolate chips, and stir until just combined. Do not over mix.
Scoop batter into greased or line muffin tins.
Bake for approx 20 minutes or until toothpick inserted in center of muffins comes out clean and tops spring back lightly when touched.