The synthesis, and dilute solution behavior of poly(2,4-dimethylphenyl methacrylate) (2,4DMP), poly(2.5-dimethylphenyl methacrylate) (2,5DMP), and poly(3,5-dimethylphenyl methacrylate) (3,5DMP) is described. Comparison is made with results reported for other bulky side chain polymers. The Kuhn-Mark-Houwink-Sakurada (KMHS) relationships were established. The unperturbed dimensions [r(2)](1/2)(0), the rigidity factor sigma, the characteristic ratio C-infinity, and the thermodynamic parameters were determined, using the Stockmayer-Fixman equation, from viscometric data in good solvents. The high rigidity observed for these polymers is explained assuming that these polymers behave as kinked-chains.