Bulk metallic glasses (BMGs) and high entropy alloys (HEAs) are amongst the most fascinating class of multicomponent metallic materials with immense potential for future applications. While most of the HEAs are designed to be crystalline alloys, some of HEAs have been designed to have amorphous structure. In the present review, the founding thermodynamic principles for both groups of materials are briefly discussed from a historical point of view. The concept of Glass-forming ability (GFA) and the criteria for the formation of BMGs are explained briefly. Structural features of BMGs and their effect on the mechanical properties are also discussed. The core effects leading to the formation of HEAs are discussed in depth with proper classification based on the microstructure. The effect of microstructure on the mechanical properties and the various manufacturing processes for the development of HEAs such as mechanical alloying, additive manufacturing, coatings and thermo-mechanical processing are highlighted. Both these classes of materials are projected to replace many conventional materials in advanced structural applications owing to their unique structural evolution. In the present brief review, the global and Indian perspectives on the research and development of these materials are critically examined. Also, as BMGs precede HEAs, the former are covered first. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022.