The emission and conductivity of anew polymerpoly (9,9-dioctylfluorenyl-2,7-diyl) end capped with polyhedral oligomeric silsesquioxanes (PFO-POSS) have been investigated by the differential approach. Thin films of PFO-POSS showed pure blue photoluminescence (PL) with structured spectrum and a maximum at lambda(PL) = 423 nm. However, the OLED structures formed on the PFO-POSS base emitted green light with broadened spectrum and a maximum at)lambda(EL) = 510 similar to 529 nm. The electroconductivity and electroluminescence have shown that the greatest influence on the current voltage and luminance current characteristics is rendered by introducing the electron transport layer to the multilayer OLED structure under investigation.