Like nitrogen-containing heterocycles, sulfur-containing heterocyclic compounds also have a lot of significant applications. These sulfur heterocycles are mainly used as a core for the synthesis of different heterocyclic compounds with various biological applications. It also occupies a huge part of natural products. In this review, we focus on the thiones-the analogous of ketones. Syntheses of thiones as well as their applications as biologically active compounds are discussed in great detail. We have considered seven different classes of thiones such as Benzimidazole thiones, Triazole thiones, Pyrimidine thiones, Thiadiazine thiones, Thiazoline thiones, Thiazolidine thiones, and Quinazoline thiones.