Preheat oven to 180C/350F.
Grease and flour your loaf pan.
In a bowl, whisk together flour, baking soda, cocoa powder, and salt.
In another bowl, whisk together sugar, oil, yoghurt, bananas, egg, and vanilla.
Add dry ingredients into wet, and mix until just combined.
Fold in chocolate chips.
Bake for 55-60 minutes or until skewer comes out mostly clean or with few moist crumbs.
Cool in pan for 10 minutes before unmoulding and cool completely on wire rack.