Grilled Swordfish and Summer Vegetables with Basil Vinaigrette

1/2 cup basil leaves
2 tablespoons red wine vinegar
2 teaspoons Dijon mustard
1 small garlic clove
1/4 cup extra-virgin olive oil, plus more for brushing
Kosher salt and freshly ground black pepper
1 yellow bell pepper
One 1 1/4-pound eggplant, halved lengthwise and cut crosswise into 1/4-inch slices
1 medium zucchini, cut on the bias 1/4-inch thick
Four 6-ounce swordfish fillets

Light a grill. In a blender, combine the basil with the red wine vinegar, Dijon mustard, garlic and 1/4 cup of the olive oil and puree until smooth. Season with salt and pepper.
Grill the bell pepper, turning frequently, until charred all over, about 8 minutes. Transfer to a plate and let cool. Discard the skin and seeds and slice the pepper 1 1/2 inch thick.
Brush the eggplant and zucchini with olive oil and season with salt and pepper. Grill over moderately high heat, turning once, until lightly charred and tender, about 4 minutes. Transfer to a platter and keep warm.
Brush the swordfish with oil, season with salt and pepper and grill, turning once, until just cooked through, about 6 minutes. Transfer to the platter, drizzle with the vinaigrette and serve, passing any remaining vinaigrette at the table.