Heat oil in a large pot over high heat. Add zucchini, eggplant, onion, poblano and bell pepper. Cook, stirring often, until the vegetables are seared and starting to soften, about 5 minutes. Stir in okra, tomatoes, water, thyme, salt and pepper; bring to a boil.
Reduce heat to maintain a low simmer; partially cover and simmer, stirring often, until the vegetables are tender, 15 to 20 minutes. Remove from heat and stir in garlic and basil. Serve warm, at room temperature or even cold.