Due to recent exporting rules, the price of germanium on the global market is surging, and the delivery is much longer than before. Zinc Sulfide (ZnS) and Zinc Selenide (ZnSe) are increasingly used as substitutes for Germanium (Ge) in infrared (IR) optics. This article offers a detailed comparison and explanation of how ZnS and ZnSe are replacing Ge as IR optics in their optical performance, thermal and mechanical properties, and costs.