Preheat the oven to 375F.
Mix pomegranate molasses, brown sugar, ketchup, honey and pineapple juice in a sauce pan, cook over medium heat for 7-8 minutes until flavors are fully combined.
Lightly coat an oven safe dish with non stick spray and spread the onion slices at the bottom of the dish.
Place the chicken thighs (skin side down) on top of the onion slices and pour the sauce on them.
Bake in the oven for 25 minutes, flip the chicken thighs and pour some sauce on them.
Bake for another 25 minutes until the chicken is fully cooked. pour the sauce again.
Serve hot with white rice.