Polyfluorene　and　its　derivatives　have　been　recognized　as　efficient　light-emitting　semiconductors.　However,　directional　alignment　of　polyfluorene　copolymers　at　a　large　scale　has　rarely　been　observed,　in　particular　for　the　two　relatively　more　amorphous　members　of　poly-9,9-dioctylfluorene-co-bethiadisazole　(F8BT)　and　poly-(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,　N0-diphenyl)-N,　N＇di(p-butyl-oxy-pheyl)-1,4-diamino-benzene)　(PFB)　molecules.　Furthermore,　the　directional　alignment　of　PFB　has　not　been　observed　so　far　due　to　the　triphenylamine　units　in　its　molecular　structures.　We　present,　in　this　work,　a　solution-processible　method　to　achieve　large-scale　alignment　of　F8BT　and　PFB　molecules　into　fibers　as　long　as　millimeters　in　a　defined　direction.　Spin-coating　the　polymer　film　on　to　a　glass　substrate　patterned　by　one-dimensional　dielectric　nano-grating　structures　through　interference　lithography　and　subsequent　modification　using　1,5-pentanediol　have　been　used　in　all　of　the　preparation　procedures.　Polymer　fibers　have　been　obtained　in　an　arrangement　parallel　to　the　grating　lines.　The　microscopic,　spectroscopic,　and　photoconductive　performances　verified　the　formation　and　the　quality　of　these　directionally-aligned　polymeric　fibers.