1. Preheat oven to 425 degrees. In a large bowl, toss broccoli with 2 tablespoons oil, coriander, cumin, 1 teaspoon salt, 1/2 teaspoon pepper and chili powder. In a separate bowl, combine shrimp, remaining 2 tablespoons oil, lemon zest, remaining 1/2 teaspoon salt and remaining 1/2 teaspoon pepper.
2. Spread broccoli in a single layer on a baking sheet. Roast for 10 minutes. Add shrimp to baking sheet and toss with broccoli. Roast, tossing once halfway through, until shrimp are just opaque and broccoli is tender and golden around edges, about 10 minutes more. Serve with lemon wedges, or squeeze lemon juice all over shrimp and broccoli just before serving.