Three generation of Boc-protected dendritic-conjugated polyfluorenes (Boc-PFP-G(0-2)) were synthesized by Suzuki coupling 1,4-phenyldiboronic ester with dendritic monomers that were synthesized through generation-by-generation approach. The gel permeation chromatography (GPC) analyses showed that the weight-average molecular weight (M-w) of Boc-PFP-G(0-2) was in the range of 11,400-20,400 Da with the polydispersity index (PDI) in the range of 1.32-1.96. Treatment of Boc-protected polymers with 6 M HCl in dioxane yielded cationic dendritic-conjugated polyfluorenes (PFP-GO(0-2)). They were soluble in common polar solvents such as DMSO, DMF, and water with absorption maxima between 345 and 379 nm. The solutions of PFP-GO(0-2) in water were highly fluorescent with emission maxima between 416 and 425 nm. Because higher generation dendrons could prevent the formation of pi-stacking aggregates of backbones of conjugated polymer, the fluorescence quantum efficiencies (QEs) of PFP-GO(0-2) enhance as the dendritic generation grew. The interactions between 25 mer double-stranded DNA (dsDNA) and PFP-G(0-2) were studied using ethidium bromide (EB) as fluorescent probe. The electrostatic bindings of PFP-G(0-2) with dsDNA/EB complex result in displacement of EB from DNA double helix to the solution accompanying by a quenching of EB fluorescence. The PFP-G(0-2) with highest generation of dendritic side chains possessed a highest charge density and could form most stable complex with dsDNA. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7462-7472, 2008