In a small bowl, combine the first five ingredients. Pour 1/4 cup into a large resealable plastic bag; add scallops. Seal bag and turn to coat; refrigerate for 20 minutes. Cover and refrigerate remaining marinade for basting.
Meanwhile, in a large saucepan, bring 3 cups water to a boil. Add peppers; cover and boil for 2 minutes. Drain and immediately place peppers in ice water. Drain and pat dry.
Drain and discard marinade. On eight metal or soaked wooden skewers, alternately thread the tomatoes, scallops and peppers.
Using long-handled tongs, moisten a paper towel with cooking oil and lightly coat the grill rack. Grill, covered, over medium heat or broil 4 in. from the heat for 3-5 minutes on each side or until scallops are firm and opaque, basting occasionally with reserved marinade. Yield: 4 servings.