The cationic oligomerization of the pyrolysis C-5 fraction in the presence of catalyst systems based on AlCl3, VOCl3, BF3 center dot O(C2H5)(2), and a Gustavson complex has been investigated. It has been shown that the use of the diisopropyl ether-modified Gustavson complex in the reaction makes it possible to synthesize fully soluble oligomers in high yields. The conversions of all the unsaturated components of the pyrolysis fraction to the oligomer at different durations of the oligomerization process have been determined. The synthesized oligomers are characterized by high unsaturation and exhibit the properties of film-forming compounds.