The results of studying effects of coal and carbonaceous wastes chemical modification on yields and properties of the thermolysis liquid products were summarized . The most effective reagents were organic substances (including liquid waste of hydrocarbon nature), halides of transition metals (ZnCl₂, FeCl₃) and alkali metal hydroxides (NaOH, KOH). In terms of increasing the yield of liquid products, the modificator maximum activity reveals in the main thermal decomposition range (300-500 º C). Their effect depends on the introducing method, the modificator content, heat treatment regime, and nature of organic raw materials.