Preheat the grill to medium-high heat.

In a large bowl, combine the olive oil, balsamic vinegar, garlic powder, oregano, salt, and black pepper.

Add the sliced vegetables to the bowl and toss until well coated.

Let the vegetables marinate for at least 10 minutes.

Place the marinated vegetables in a grill basket.

Grill the vegetables for about 10-15 minutes, turning occasionally, until they are tender and have grill marks.

Remove from the grill and serve warm.