Place the ¼ cup olive oil, 2 cloves finely minced garlic, zest from 1 lemon, juice from 1 lemon, zest from 1 orange, juice from 1 orange, ½ teaspoon dried basil, ½ teaspoon dried oregano, and ¼ teaspoon dried thyme in a resealable bag. Seal and shake to mix.
Place the 2 boneless skinless chicken breasts cut in half in the bag, seal, and shake until the chicken is coated with the marinade.
Refrigerate and marinate for at least 30 minutes or up to 2 hours. Preheat the grill or a grill pan over medium-high heat.
Remove the chicken from the marinade and season both sides generously with salt and pepper to taste. Grill for 4-5 minutes on each side or until chicken is cooked through.
Remove from the grill and let the chicken rest for 5 minutes. Sprinkle with 2 tablespoons chopped parsley and serve with lemon wedges for serving if desired.