Preheat oven to 350F Lightly coat a 9 x 5 inch loaf pan with canola oil cooking spray.
In a medium bowl, whisk together the flour, baking soda, salt, and spices.
In a large bowl, whisk together the pumpkin puree, egg, vanilla, and molasses. Whisk in the mashed bananas.
In a small bowl, whisk together the buttermilk and yogurt.
Add half of the dry ingredients into the wet and stir until almost fully moistened. Stir in half of the buttermilk and yogurt mixture. Stir in the remaining dry ingredients, followed by the remaining buttermilk and yogurt. Stir until just fully moistened. Fold in the chocolate chips, if desired.
Spoon batter into the prepared loaf pan, smoothing the top to create an even surface. Bake about 50 minutes - until a toothpick inserted into the center of the loaf comes out clean.