The stabilization of supercooled metallic liquid occurs for a number of alloys where the constituent elements have the following three rules, i.e., multi-component of more than three elements, significant mismatches of atomic size above 12% among the main three elements, and negative heats of mixing among their main elements. The use of the stabilized supercooled liquid has enabled us to synthesize a number of novel advanced metallic materials. In this review, we present the alloy components, fabrication processings, structures, mechanical properties and applications of high-strength Al- and Mg-based alloys with glassy, nanocrystalline or nanoquasicrystalline phase which were developed on the basis of the concept of the utilization of stabilized supercooled liquid for the last one decade.