Step 1

For marinade, place first 5 ingredients in a blender. Cut 4 tomatoes into quarters and add to blender; cover and process until blended. Halve remaining tomatoes for grilling.

Step 2

In a bowl, combine chicken and 2/3 cup marinade; refrigerate, covered, 1 hour, turning occasionally. Reserve remaining marinade for serving.

Step 3

Drain chicken, discarding marinade. Place chicken on an oiled grill rack over medium heat. Grill chicken, covered, until a thermometer reads 165°, 4-6 minutes per side. Grill tomatoes, covered, over medium heat until lightly browned, 2-4 minutes per side. Serve chicken and tomatoes with reserved marinade.