Polymer film and polymer film device using same

A polymer film comprising a polymer having liquid crystallinity, having a number-average molecular weight in terms of polystyrene of 103 to 108 and having an electron mobility or hole mobility of 10−5 cm2/Vs or more, and having a film thickness in the range from 1 nm to 100 μm,

• wherein the polymer contains repeating units of the following formula (1-1), (1-2), (1-3), (1-4) or (1-5):
• wherein X represents a hetero atom or a divalent group containing hetero atoms, and A ring, B ring, C ring, D ring, E ring, F ring and G ring each represent independently an aromatic ring optionally having a substituent selected from the group consisting of alkyl groups, alkoxy groups, alkylthio groups, aryl groups, aryloxy groups, arylthio groups, arylalkyl groups, arylalkoxy groups, arylalkylthio groups, arylalkenyl groups, arylalkynyl groups, amino groups, substituted amino groups, silyl group, substituted silyl groups, halogen atoms, acyl groups, acyloxy groups, imino groups, amide groups, imide groups, monovalent heterocyclic groups, carboxyl group, substituted carboxyl groups and cyano group.