1Heat closed medium-size contact grill for 5 to 10 minutes. In large bowl, mix butter, lemon juice, garlic powder and 1/2 teaspoon of the lemon pepper. Add shrimp; toss to coat.
2Place shrimp on grill. Close grill. Grill 4 to 6 minutes or until shrimp are pink and firm.
3Meanwhile, in small bowl, mix mayonnaise, bell peppers, basil, lemon peel and remaining 1/4 teaspoon lemon pepper. Serve with shrimp.