Preheat an outdoor grill for medium-low heat and lightly oil grate.
Place the ears of corn on the grill and cook until the kernels are tender, about ten minutes turning frequently. Remove the ears from the grill and cool. Cut the kernels off of the cob.
Fill a large saucepan with lightly salted water and bring to a boil over high heat. Add asparagus and cook until just tender, about 1 minute. Drain in a colander and rinse immediately under cold, running water until well chilled. Set aside.
Combine the corn, asparagus, roasted peppers, garlic, basil, olive oil, and balsamic vinegar in a large bowl; season with salt and pepper to taste. Serve at room temperature or chilled.