Cationic cooligomerization of styrene and dicyclopentadiene, being main polymerizable components of C 9 fraction of liquid pyrolysis products of hydrocarbon feed, has been studied. Dependence of the cooligomer yield and properties including average molecular weight, softening point, bromine number, colour, and density on styrene/dicyclopentadiene ratio in the reaction mixture have been determined. Cooligomerization was carried out in solution using AlCl 3 based liquid catalytic complex and silica-alumina acid type catalyst that made it possible to compare the catalysts.