In a resealable plastic bag, combine wine, onion, Worcestershire and coriander. Add steak and Peppers; seal bag. Marinate, refrigerated, for 48 hours (or as long as possible).
Heat grill to medium to medium-high heat. While grill is heating, remove brisket from marinade. Strain marinade into a large bowl; add pepper pieces.
Grill peppers 5 minutes, then turn over and grill an additional 5 minutes. Transfer to a platter, drizzle with olive oil and sprinkle with some salt and pepper. Cover to keep warm.
Place brisket fat-side down on grill. Cook 13 minutes; reduce heat to medium if getting too browned. Turn meat over and continue to cook 16 to 18 minutes more or until meat registers 145 degrees F on an instant-read thermometer. Add meat to platter with peppers; cover with foil. Let rest 5 minutes and slice.