The theological characterization for a set of structurally diverse core cross-linked star (CCS) polymers is presented. The influence of arm molecular weight (M-w(arm)) and CCS polymer molecular weight (M-w(CCSP)) on the steady- and dynamic-shear properties determined by plate rheometry will be discussed. Both these parameters dramatically affect the CCS polymer solution properties and determine its "molecular softness"; a key feature of star polymers. Data from light scattering and capillary viscometry analysis are also presented to relate the dimensional configuration of the CCS polymers to their rheological properties. The methodology for tuning the structure of the CCS polymer is provided and the implications on solution properties are discussed. (C) 2008 Elsevier Ltd. All rights reserved.