Thermolysis of perbenzylated D-glucopyranosediyl diazide 1 and D-galactopyranosediyl diazide 4 afforded, respectively, the corresponding 6-oxa-1,5-pentamethylenetetrazoles 2 and 5via the sugar azido nitrenes, while, photolysis of diazides 1 and 4 gave, respectively, compounds 2 and 5 together with the corresponding by-products, 10-oxa-1,5-pentamethylenetetrazoles 3 and 6. Similarly, 5-(sugar chain)-substituted tetrazole 9 was obtained by the thermolysis of perbenzylated 1,1-diazido acyclic sugar 8, while compound 9 and 1-(sugar chain)-substituted tetrazole 10 were formed by the photolysis of compound 8. Interestingly, the thermolysis and photolysis of 1,1-diazido-2,3-di-O-benzyl-D,L-glyceraldehyde 8f gave both the corresponding 9f and 10f.