Through in situ reduction of a gold precursor, we have tethered gold nanoparticles (An NPs) to the side chains of poly(2,7(9,9'-dioctylfluorene)-co-4-diphenylamino-4'-bipenylmethylsulfid e) (PF-DBMS) through its ArSCH3 anchor groups. The presence of 1 wt % of the tethered Au NPs led to a reduction in the degree of aggregation of the polymer chains, resulting in a 50 % increase in its quantum yield. ne electroluminescence of a 1 wt % Au/PF-DBMS device was almost four times higher in terms of its maximum brightness and its full-width-at-half-maximum emission peak was much narrower than that of a pure PF-DBMS device; the presence of a small amount of Au NPs significantly enhances the electron injection and transport and suppresses the photo-oxidation of PF-DBMS.