Sialons are the spotlight of current investigation as low-cost and outstanding alternatives to the currently used metal alloys in various applications. The excellent high-temperature properties, high mechanical properties, structural reliability, good sinterability, easy densification with its low-cost processing make them superior candidates in many applications such as automotive engines, high-performance bearings, wear components, and gas turbine blades. In addition, the existence of two interstitial crystallographic sites in their crystal structure gives the opportunity to accommodate some rare earth element activators such as Eu²⁺, Yb²⁺, Ce³⁺, and Pr³⁺. These types of sialon-based materials have recently found a new promising application as a luminescent material for white light-emitting diodes. The aim of this review is to survey and provide a comprehensive look at the most relevant and significant publications regarding the development of sialons and their processing into both structural and luminescent materials. Such information forms a database that could enable scholars and engineers to tailor a final product derived from sialons with specific characteristics for a certain application. This review article should be of concern to engineers and scientists interested in the development and utilization of sialons for structural and wLEDs applications.