A novel 2'-O,4'-C-bridged nucleic acid, 3,4-dihydro-2H-pyran bridge moiety (DpNA), with a dioxabicyclo[3.2.1]oct-3-ene ring was designed. Construction of the dihydropyran bridge was achieved by dehydration of a six-membered hemiacetal ring, and the DpNA monomer was synthesized in 10 steps from 5-methyluridine (total yield 9%). The synthesized DpNA monomer was incorporated into oligonucleotides to examine the properties of the modified oligonucleotides. The DpNA-modified oligonucleotides possessed high affinity toward ssRNA and were more resistant to nucleases compared to the corresponding natural oligonucleotide.