The effects of some additives(black liquor, wood and lignin) on the conversion of coal and product were investigated in the lab-scale, high pressure reacting system around $375^{circ}C$. The addition of lignin to coal during liquefaction significantly increased the depolymerization of coal and enhanced the quality of the liquid products. Coprocessing of wood and coal at $400^{circ}C$ increased yield of liquid product about 8%, but higher temperature above $400^{circ}C$ reduced liquid product due to increase of gas products. The addition of black liquor resulted in an enhancement in coal conversion yields, however, the observed increase is lower than that obtained in the presence of NaOH because lignin present in black liquor is not very effective due to the $OH^-$ presence.