Preheat grill to medium-high heat, approximately 400°F (204°C).
Brush zucchini slices and corn ears with 1 tablespoon of olive oil.
Grill corn for 12-15 minutes, rotating occasionally until charred on all sides.
Grill zucchini slices for 3 minutes per side until tender with distinct grill marks.
Remove vegetables from grill and allow to cool slightly; slice corn kernels off the cob.
In a large mixing bowl, whisk together the remaining 2 tablespoons olive oil, lemon juice, honey, salt, and pepper.
Add grilled zucchini, corn kernels, and diced bell peppers to the bowl.
Toss ingredients gently to combine with the dressing.
Garnish with crumbled feta cheese and fresh basil before serving.