1) Heat large saute pan on grates of the barbecue over medium heat. Add couscous and toast until lightly golden brown. Grill vegetables.
2) Bring 1.5 litres of water to the boil over high heat, add 1 tablespoon salt and toasted couscous and cook until al dente. Drain well and place in a large bowl.
3) Add grilled vegetables, olives, basil, and vinaigrette and toss until combined; season with salt and pepper. Let sit at room temperature for 30 minutes before serving or cover and refrigerate.