1,2,3-Triazoles having sugar chains at C-4, and others having the chain at N-1, were prepared. Condensation of 3- O-acetyl-4,5- O-isopropylidene-1-pentyne- D- threo-3,4,5-triol ( 1) with phenyl azide, followed by removal of substituents, gave 1-phenyl-4-( D- threo-trihydroxypropyl)-1,2,3-triazole ( 2), whose structure was proved by oxidation to known derivatives of 1-phenyl-1,2,3-triazole. The 1-benzyl analog ( 4) of 2 was prepared similarly. The 4- C-substituted 1,2,3-triazole 12 was obtained in the same way from the acetylenic sugar derivative 11. By condensing phenylacetylene with the sugar azides 13 (primary azide), 15 (secondary azide), and 17 (glycosyl azide), the 1-substituted 4-phenyl-1,2,3-triazoles 14, 16, and 18, respectively, were obtained. The 4-substituted 1-phenyl-1,2,3-triazoles and 1-substituted 4-phenyl-1,2,3-triazoles here reported show π→π* absorption near 246 nm, in contrast to the 4-substituted 2-phenyl-1,2,3-triazoles (phenylosotriazoles), which absorb near 268 nm. The optical rotatory dispersion spectrum of 2 shows a negative Cotton effect and is closely similar to that of the 2-phenyl analog ( D- threo-pentulose phenylosotriazole).