To prepare the marinade, combine the parsley, basil, garlic, oil, salt and pepper in a zip-close plastic bag. Add the shrimp. Refrigerate, turning the bag occasionally, 1 hour to overnight.
Spray a nonstick ridge grill pan with nonstick spray and set over medium-high heat. Working in batches, if necessary, grill the shrimp until they are just opaque in the center and lightly browned on the outside, 2-3 minutes on each side.