The Internet of Things (IoT) has extensively impacted our lifestyles. However, IoT networks’ large size and widespread nature remain significant obstacles to IoT privacy. Furthermore, the decentralized nature of blockchain has solved numerous problems related to safety, authentication, and maintenance in IoT systems. A smart city as an intelligent society can be created in this digital age of rapid communication. It aims to review a wide range of literature to assess the safety challenges and problems associated with implementing blockchain technology for sustainability and smart governments. The convergence of blockchain technology and artificial intelligence is a unique catalyst for technological transformation in IoT applications that are intelligent and sustainable. Sustainable IOT applications could be advanced and developed through the use of blockchain. The discussion led us to develop a framework for processing and obtaining required information leveraging IoT devices, security, and privacy. Through digital analytics and storing results in decentralized cloud repositories, blockchain technology promotes a wide range of applications.