Preheat grill. Brush bread slices with olive oil and grill lightly on each side to toast. Arrange bread on a baking sheet.
Preheat oven to 400 F. Spread each bread slice with 1 tbsp pesto sauce. Top with slices of mozzarella and then sprinkle with sun-dried tomatoes and Parmesan cheese. Bake for 5-6 minutes or until cheese softens.
Serve immediately.