2â²-O-(1-Naphthyl)uridine and 2â²-O-(2-naphthyl)uridine were synthesized by a microwave-mediated reaction of 2,2â²-anhydrouridine with naphthols. Using the 3â²-phosphoramidite building blocks, these 2â²-O-aryluridine derivatives were incorporated into 2â²-O-methylated oligoribonucleotides. Incorporation of five 2â²-O-(2-naphthyl)uridines into a 2â²-O-methylated RNA sense strand significantly increased the thermostability of the duplex with a 2â²-O-methylated RNA antisense strand. Circular dichroism spectroscopy and molecular dynamic simulation of the duplexes formed between the modified RNAs and 2â²-O-methyl RNAs suggested that there are ÏâÏ interactions between two neighboring naphthyl groups in a sequence of the five consecutively modified nucleosides.