Polyindene was prepared by the controlled cationic polymerization of indene initiated with cumyl methyl ether/TiCl4 in CH2Cl2 at -65 degreesC. The number-average molecular weight was controlled by the ratio of monomer to cumyl methyl ether; polydispersity indicies ranged from 1.8 to 3. Polyindene samples prepared by this technique were characterized by H-1 and C-13 NMR spectroscopy, and a corrected assignment of chemical shifts in these spectra was made with respect to previous literature reports. Polyindene samples ranging from M-n = 5 to M-n = 70 kg/mol were hydrogenated to high levels of phenyl ring saturation using a heterogeneous catalyst consisting of silica-supported Pt. Characterization of polyindene and its hydrogenation product by size exclusion chromatography using a light-scattering detector showed that the hydrogenation proceeded without change in the degree of polymerization. The relationship between molecular weight and the glass transition temperature for these polymers was established, and T-g values of 207 degreesC for polyindene and 268 degreesC for hydrogenated polyindene were predicted in the limit of infinite molecular weight.