Cobalt-molybdenum-containing thiosalts with different composition of the sulfonium cation are prepared. The activities of sulfide catalysts in situ synthesized on their basis in the hydrogenation of substituted naphthalenes are compared. It is shown that the sulfonium cation composition affects the morphology of the sulfide particles and the phase composition of the catalyst. It is demonstrated that the conversion of model alkyl-substituted bicyclic aromatic hydrocarbons is higher in the presence of the catalyst prepared from the phenylsulfonium thiosalt.