An effective method to control polydispersity (M-w/M-n) in the oxidative coupling polymerization of 2,6-dimethyl phenol has been developed. SBA-15 functionalized with N,N,N'-trimethyl-N'-trimethoxysilylpropylethylenediamine and copper chloride(I) produced a polymer with the number average molecular weight (M-n) of 44000 and M-w/M-n of 3.9, when the polymerization was conducted in toluene/pyridine (5/1 volume ratio) at 40 degrees C for 12 h under oxygen atmosphere. The conventional catalytic system [CuCl(I)-pyridine] afforded the polymer with M-n of 81000 and M-w/M-n of 40, indicating the effectiveness of the mesoporous catalyst.