The process of modern urbanization necessitates significant advancements in social, environmental, and economic aspects to enhance the overall quality of life in cities. This evolution has given rise to the concept of "Smart Cities." The incorporation of cutting-edge technologies such as blockchain, the Internet of Things (IoT), and other innovative communication systems has accelerated the progress towards the establishment of the sixth-generation communication intelligence, commonly known as 6G.Connected to the blockchain in smart cities is a crucial key, and researchers conducted an in-depth analysis of prior research to elucidate the pivotal contributions, ensuring a clear understanding of the state-of-the-art in sixth generation blockchain for smart cities. This study aims to pave the way for future research by examining key technologies, scenarios, challenges, and associated issues. Exploring the obstacles in deployment that require resolution before the implementation of block intelligence in 6G networks, this study aims to establish a foundational understanding for forthcoming advancements in blockchain technology within this generation. The paper outlines prospective research areas critical for the evolution of blockchain in the 6G era. Additionally, it addresses the challenges associated with integrating blockchain amidst the advancements in computing and mobile communication technologies, offering insights into the complexities that need to be navigated for a successful efficiency.