Infrared spectroscopy, ubiquitous in contemporary chemical laboratories, is frequently underutilised for just the basic characterisation of products. However, its unique ability to provide rich molecular-level information, its simplicity and flexibility for various applications, and its ability to be combined with a variety of techniques, make it one of the most useful techniques for a deep understanding of the microscopic background of chemical and physical phenomena, especially those of relevance for materials applications. This tutorial review puts a spotlight on IR spectroscopic investigations in materials science by providing a critical insight into the state of the art, covering both fundamental aspects and illustrative examples of its utilisation, as well as current challenges and perspectives focusing on physical and chemical transformations in the solid state.