This study investigates the potential of AI tools, GPT-4 and DALL-E, in generating sustainable urban design concepts addressing key issues like urban heat islands, walkability, and green spaces. Through a systematic methodology, the study demonstrates the ability of these tools to generate novel ideas, while also revealing limitations in feasibility, context-specificity, and the need for human expertise. The paper discusses the ethical implications of AI in urban design and highlights the need for responsible deployment. The study contributes to the discourse on AI's role in sustainable urban development and identifies avenues for future research.