Coronene and dibenzo[cd,/rn]perylene, which are very planar References molecules, have very large k' values and deviate positively from the linear relationship between F and log k'. A possible explanation is that ashape-shape recognition between the solute and the stationary phase strongly controls their retention, i.e. the shape of the solutes corresponds to substructures in dicoronylene, which lead to high level of interaction between surface areas.One can conclude, therefore, that the retention behavior observed with polymeric ODS (non-planar PAHs show exclusion-type retention behavior) is caused bytheir"s1it-like"structure, because the highly planar stationary phase dicoronylene shows a similar retention behavior for non-planar PAHs. Also, the investigation described here opens up the possibility of designing a more effective LC stationary phase suitable for PAH isomer separation where planarity would differentiate the compounds.