We present aromatic thioketones as an excellent set of compounds for investigations of kinetics of fast bimolecular reactions studied by fluorescence quenching. It would be interesting to study seven compounds with fluorescence lifetimes ranging from 64 ps for thioxanthione to 880 for 2,23,3-tetramethylindanthione in perfluoro-1,3-dimethylcyclohexane. Moreover the kinetics of fluorescence decay of all the studied thioketones in perfluoroalkanes without a quencher is very well established with xanthione as one of the most thoroughly studied compounds. Previous theoretical work has suggested that investigations of the kinetics of quenching involving compounds with very short fluorescence lifetimes would be a promising avenue of approach to obtaining more definitive experimental information for modelling studies. The aromatic thioketones are such donors. For xanthione, with a lifetime of 178 ps, and 1,3,4,5,6,8-xanthione-d6, with a lifetime of 600 ps, the kinetics of quenching can be described satisfactorily by the SCK theory. Parameters such as the sum of donor and quencher radii and the sum of their diffusion coefficients, obtained from this theory, are in rather good agreement with the corresponding values determined by other methods. Unfortunately, a rather large uncertainty in the determination of the proper rate constant k, prevents obtaining an unambiguous answer to the question of whether the large values of k are characteristic of the systems studied or instead are a consequence of the model employed. Also the mechanism of quenching of the S2 states of the thioketones by hydrocarbons is not yet clear.