In a 2-cup measuring cup, combine the brown sugar, salad dressing, pineapple juice and soy sauce. Pour 2/3 cup into a large resealable plastic bag; add the pork chops. Seal bag and turn to coat; refrigerate for at least 3 hours or overnight. Cover and refrigerate remaining marinade for basting.
Drain and discard marinade. Grill, uncovered, over medium heat for 4 minutes on each side or until a thermometer reads 145°. Remove from heat and keep warm. Place pineapple slices on grill. Baste pineapple with reserved marinade. Grill 2-3 minutes on each side or until browned Let meat stand for 5 minutes before serving. Place a pineapple slice on each chop. Yield: 6 servings.