Large-area　dual-phase　plasmonic　gold　nanostructures　were　produced　using　the　phase-separation　pattern　of　a　polymer　blend　film,　where　two　typical　light-emitting　polymeric　semiconductors　of　poly　(9,9-dioctylfluorene-co-benzothiadiazole)　(F8BT)　and　poly　(9,9-dioctylfluorene-co-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4　phenylenediamine)　(PFB)　have　been　employed　to　construct　the　heterojunction　patterns.　The　laser-induced　selective　cross-linking　of　F8BT　molecules　and　the　subsequent　rinsing　process　using　the　good　solvent　of　chloroform　for　PFB　supplies　a　stable　template　for　a　further　metallization　process.　When　colloidal　gold　nanoparticles　were　spin-coated　onto　the　surface　of　the　template,　a　majority　of　the　gold　nanoparticles　were　confined　into　the　holes　of　originally　PFB-rich　phase,　while　a　minor　portion　stays　on　the　ridges　of　F8BT-rich　phase.　After　the　annealing　process,　larger　gold　nanoparticles　were　produced　inside　the　holes　and　smaller　ones　on　the　ridges,　which　induced　localized　surface　plasmon　resonance　in　the　near　infrared　and　in　the　visible,　respectively.　The　structural　parameters　of　the　gold　plasmonic　pattern　can　be　tuned　by　different　surface　modification　and　annealing　processes,　which　can　tune　the　spectroscopic　response　in　the　spectral　position　and　in　the　spectral　intensity.　The　produced　nanostructures　with　broadband　plasmon　resonance　can　be　used　as　a　template　for　random　lasers　with　strong　optical　scattering　at　both　the　pump　and　emission　wavelengths　and　for　photovoltaic　devices　with　strong　absorption　in　the　visible　and　near　infrared.