Soak toothpicks in water. In a large bowl, combine pineapple juice, orange juice, soy sauce and brown sugar. Add pineapple chunks and cover. Chill for 1 hour to marinate.
Preheat oven to 400F.
Line a rimmed baking sheet with foil or parchment. Wrap each pineapple chunk with 1/2 slice of bacon and secure with a toothpick.