The base flip-inducing nucleic acids are expected to create a specific field for various chemical reactions. We now report a novel type of base-flip-inducing oligodeoxynucleotide and photo-cross-linking reaction. Two 3-arylethynyl-5-methyl-2-pyridone nucleosides, Ph and An, were synthesized, and their properties were investigated. The alkyne-alkyne photo-cross-linking rapidly proceeded by taking advantage of the base-flipping-out field where two alkynes overlap each other. This photo-cross-linking would be a new candidate to form cross-linked DNAs.