Macrocyclic polystyrenes prepared by a single-step, pseudo-unimolecular cyclization of a linear alpha-(diethoxyethyl)-omega-styrenylpolystyrene can effectively be analyzed by liquid chromatography at the critical point of adsorption. Using silica gel as the stationary phase and THF-hexane as the eluent, the macrocyclic oligomers are separated from their linear precursors and other nonfunctional linear oligomers. The quantitative determination of the cyclization yield can be carried out via appropriate detector calibration for the linears and cyclics. Additional information on the chemical structure of the linears and cyclics is obtained by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. In conclusion, a possible cyclization mechanism is given including an interpretation of the MALDI behavior of the samples.