Electroluminescent devices with double organic layers were fabricated using polymeric materials as the hole transport layer and tris(8-quinolinolato)aluminum(III) complex (Alq) as the emitting layer, respectively. The polymeric materials used are poly(methylphenylsilane), plasma-polymerized carbon disulfide, and polycarbonate (TPD). A cell structure of glass substrate/indium-tin-oxide (ITO)/polymer layer/Alq/Mg:Ag (10:1) or Mg/Ag was employed. Among the polymeric systems, the doped PC system affords efficient electroluminescence from the Alq layer. In this cell, bright green emission with luminance of 7,700 cd/m2 was observed at a drive voltage of 16 V. Single-layer-type EL devices were also fabricated using poly(methyl methacrylate) (PMMA) molecularly doped with both TPD and Alq. A cell structure of glass substrate/ITO/doped PMMA/Mg:Ag (10:1) was employed. Green emission with luminance of 920 cd/m2 was achieved for a cell with a TPD/Alq ratio of 0.67 at a drive voltage of 17 V, and the EL color was tuned to blue-green and yellow-orange by further doping the PMMA layer with suitable organic dyes.