A series of ter(9,9-dialkylfluorene)s (TFs) containing cyclohexyl and hexyl side groups has been synthesized via the Suzuki coupling reaction. Their chemical structures were characterized by H-1 NMR and C-13 NMR. All TFs were soluble in common organic solvents and showed good thermal stability up to 400 degrees C. In particular, T(CHC)F composed of two 9,9-bis(cyclohexylmethyl)fluorenes and one dihexylfluorene showed improved thermal stability over T(HHH)F and was found to be amorphous, unlikely with T(CCC)F. A light-emitting diode device fabricated with an ITO/2-TNATA/NPB/TFs/Alq3/Liq/Al configuration exhibited blue light emission with EL maxima at 450 nm and EL efficiency of 1.1 cd/A.