A novel hyperbranched conjugated poly(fluorene) (Hyper-PDHF) was obtained through the Suzuki coupling polymerization. Hyper-PDHF has good solubility in common organic solvents and showed good thermal stability up to 428 degrees C with less than 5 wt% weight loss. The photophysical properties of Hyper-PDHF in solution and net solid film are inspected and compared with poly(di-n-hexylfluorene) (PDHF) having linear structure. An absorptionmaximum of Hyper-PDHF film was determined at 334 nm which was far blue shifted than that of linear PDHF film (381 nm). Hyper-PDHF showed absolute blue photoluminescence (PL) peak at 418 nm with 394 and 444 nm as shoulder peaks. Hyper-PDHF showed also high fluorescence quantum yield as about Phi(sol) = 0.81. In addition, Hyper-PDHF film exhibited almost no longer wavelength emission peaks even the film was annealed at 80 degrees C for 1 hr with illuminating UV (365 nm) in air condition. The high PL efficiency and no aggregate or excimer emission of Hyper-PDHF results from the inhibition of intramolecular or intermolecular interaction by the introduction of the hyperbranched network into the poly(fluorene) backbone.