Cyclization reaction products by the end-to-end ring closure of telechelic polystyrenes (PSs) with molecular weight of 47 k and 380 k in THF (good solvent) and also in cyclohexane (poor solvent) were characterized by SEC connected with multi-angle light scattering (MALS). By comparison of the SEC peaks of the monomeric rings from 47 k-PSs in THF and cyclohexane, there is no essential difference both in molecular weight and in molecular weight distribution between the two monomeric rings formed. On the other hand, comparing the data for monomeric rings from 380 k-PSs in THF and cyclohexane by SEC-MALS, it has been found that the ring formed in cyclohexane has the same molecular weight as that of the ring formed in THF, while the former reveals the lower radius of gyration than that of the ring formed in THE These results clearly indicate the evidence of the formation of knotted ring polymers by experiment for the first time. (c) 2009 Elsevier Ltd. All rights reserved.