Stir the broth, thyme and black pepper in a small bowl. Brush the vegetables with the broth mixture.
Lightly oil the grill rack and heat the grill to medium. Grill the vegetables for 10 minutes or until they're tender-crisp, turning over once during cooking and brushing often with the broth mixture.
Tip: A grilling basket is handy for grilling smaller foods like these veggies. Just place the vegetables in a single layer in the basket, close and place on the grill. You can baste the vegetables right in the basket, and flip the basket to grill the other side.