Raman spectroscopy is a powerful tool to study molecular systems. The influence of the non-covalent interactions of two different lengths of oligonucleotides, 10-base and 25-base, composed of polyA, polyT, polyG and polyC, on the electronic structure of single-walled carbon nanotubes (SWCNTs) is first studied by means of Raman spectroscopy. Then, the possible changes in their electronic structure with chemical attachment of the oligonucleotides are investigated. The Raman data indicates that polyA with 10-base wraps the SWCNTs at increased incubation time, while polyA with 25-base wraps quickly, but increasing the incubation time reduces the efficient wrapping, possibly due to the self-stacking. The polyT-10 does not wrap around the SWCNTs very effectively even at increased incubation times, but the polyT-25 wraps them effectively in 30 mins, but increasing the time again decreases the wrapping significantly. While polyG shows similar pattern to the case for the polyA, the polyC shows much higher affinity for the SWCNTs under all studied conditions. The chemical attachment of the same oligonucleotides does not alter the electronic properties of the SWCNTs significantly. These results suggest that oligonucleotides can be used to bring the SWCNTs into higher structures through DNA hybridization without significantly altering their unique properties. Copyright © 2012 John Wiley & Sons, Ltd.