Preheat a grill to medium high. Mix the yogurt, garlic, parsley and oregano in a bowl. In a separate bowl, toss the chicken with 1/4 cup of the yogurt mixture, 1/2 teaspoon salt, and pepper to taste. Stir the olive oil into the remaining yogurt mixture and set aside.
Brush the cut sides of the eggplant with olive oil and sprinkle with salt and the smoked paprika. Brush the bread with olive oil.
Brush the grill grates with olive oil. Grill the chicken, turning once, until cooked through and a thermometer inserted into the thickest part registers 160 degrees F, 15 to 20 minutes. Meanwhile, grill the eggplant, skin-side down, until softened, about 15 minutes; turn and continue cooking until tender, about 5 more minutes. Grill the tomatoes and bread, turning once, until marked, 2 to 3 minutes.
Serve the chicken, eggplant, tomatoes and bread with the yogurt sauce.
Per serving: Calories 545; Fat 18 g (Saturated 4 g); Cholesterol 98 mg; Sodium 795 mg; Carbohydrate 47 g; Fiber 6 g; Protein 47 g