We have synthesized a class of blue-emitting polymers based on a donor-acceptor architecture composed of oxadiazole and carbazole moieties containing various substituted groups in the same side chain. Depending on the substituted group at carbazole, they showed different thermodynamic properties: two polymers containing N-methylcarbazole showed liquid-crystalline behavior. The single-layer polymer light-emitting diodes using these polymers exhibited blue emission with peaks from 430 to 440 nm. The device using the liquid-crystalline polymer with an alignment layer emitted polarized blue light with a dichroic ratio of 5.1.