Over the past few decades, ionic liquids, nanofluids, nanomaterials, and nanotechnology have led to the ability to perceive their innovative changes in various scientific and industrial fields. Ionic liquids, that are well-known for their peculiar physicochemical properties, offer versatile solvent alternatives in chemical processes and green technologies. Their tunable nature and low volatility make them easily suitable for applications from catalysis to energy storage. Nanofluids consist of nanoparticles in traditional fluids; they possess features of better thermal conductivity as well as heat transfer than their base liquids. These features can become exciting purposes for their use in advanced thermal management systems, improved heat exchangers, and biomedical applications. Nanomaterials are revolutionizing material science and engineering, generating dimensions at the nanoscale and engineered properties. It enables lighter yet stronger materials, new sensors, and targeted drug delivery systems, which will deliver progress across sectors. These advancements are embedded in the field of nanotechnology, which deals with manipulating matter at the atomic and molecular scales to develop new functionalities and applications. Nanotechnology integrates principles from diversified streams such as physics, chemistry, biology, and engineering that deal with the design and fabrication of structures with utmost precision and control. The current chapter presents the most basic, state-of-the-art, and wide-ranging applications of ionic liquids, nanofluids, nanomaterials, and nanotechnology. It’s more or less about their characterization methods and the main prospective research and applied paths in these areas. This chapter elucidates all their synergistic interactions and multidisciplinarity, equally catering to researchers, engineers, and students who would like to probe these novel technologies at the frontier of modern science and technology.