Poly(9-fluoreneyl methacrylate) was obtained through anionic polymerization with t-BuLi and t-BuMgBr and through radical polymerization with alpha,alpha'-azobisisobutyronitrile. Anionic polymerization with t-BuLi in tetrahydrofuran and radical polymerization afforded syndiotactic polymers (rr similar to 90%), whereas anionic polymerization with Li and Mg initiators in toluene and CH,Cl, led to isotactic polymers. The thermal and photophysical properties of the polymers were examined. A syndiotactic polymer tended to show higher glass transition and decomposition temperatures than an isotactic polymer. However, polymers with different tacticities were not likely to assume specific, distinctive conformations such as a helix or a pi-stacked conformation in solution. An isotactic polymer showed stronger interactions in a CH,Cl, solution with 2,4,7-trinitro-9-fluorenylidenemalononitrile, an electron-acceptor molecule, than a syndiotactic polymer. (C) 2004 Wiley Periodicals, Inc.