Slice 4-3/4" thick pieces of bread from loaf. Brush one side of each with oil. Place on hot grill (may use broiler) until toasted. While browning, brush other side with oil, turn and toast. Remove from grill. Place toasted bread on a cookie sheet and top each with pesto.
Slice eggplant into 1/2" slices. Cook eggplant in the same manner as bread.
Remove eggplant from grill or broiler and place each slice on top of each slice of bread. Place one piece of roasted pepper on top of each slice of eggplant and one slice of mozzarella cheese on top of each pepper. Bake in 450° oven until cheese melts. Remove and serve at once on a bed or marinara sauce. Serves 4.