Materials Engineering based on Nano Sciences is a key ingredient of current advanced technologies supporting modern society, especially Information and Energy Technologies. The tremendous rapid growth of these fields makes them highly interdisciplinary and then inevitably demands their mutual interactions. Under these circumstances, the 2021 5th International Conference on Materials Engineering and Nano Sciences (ICMENS 2021) was organized as a series of successful international conferences held in Singapore (2017), Hong Kong (2018), Hiroshima (2019, Japan), and Pattaya (2020, Thailand). The main goal of ICMENS 2021 is to address latest original results in Materials Engineering and Nano Sciences, including both theoretical advances and practical implementations, which are becoming more and more popular in industry and in our daily lives. The ICMENS 2021 will provide a premier interdisciplinary platform for scientists, researchers, industry leaders, engineers and educators throughout the world to present and discuss the most recent innovations, trends, concerns, as well as practical challenges encountered, and streamline solutions in the fields of Materials Engineering and Nano Sciences. The meeting will provide an opportunity to highlight recent developments and to identify emerging and future areas of growth in Quantum Technology.