An electrochemical synthesis of series of functionalized poly(alkyldioxythiophene) derivatives in ionic liquids was undertaken. Poly(3,4-propylenedioxythiophene) (PProDOT), poly(3,4-dimethylpropylenedioxythiophene) (Me-2-PProDOT) and poly(3,4-diethylpropylenedioxythiophene) (Et-2-PProDOT) were electrodeposited in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. These conjugated polymer based thin films were then exploited as label-free oligonucleotide (ODN) sensors. It was found that electrochemical properties of the polymer are unaffected in the presence of a noncomplementary ODN, contrary to this, significant changes can be observed on addition of a complementary ODN target, in the electrolytic medium. Further lower value of current obtained in oxidized states in double strand nucleotides indicates increases in stiffness of polymer structures (C) 2013 Elsevier Ltd. All rights reserved.