Introduction 4207 2. Nucleosides 4207 2.1. Base Modified Nucleosides 4207 2.2. Sugar Modified Nucleosides 4211 2.3. Nucleoside Bioconjugates 4214 3. Oligonucleotides 4216 3.1. 1,2,3-Triazole as Replacement of the Phosphodiester Linkage 4216 3.2. 1,2,3-Triazole as Linker for Solid Supported Synthesis 4217 3.3. Post-and Presynthetic DNA Modifications 4217 4. Conclusion 4219 5. Acknowledgments 4219 6. References 4219 Jong Hyun Cho was born in Gim-hae, South Korea, in 1967. In 2002, he received his Ph.D. in Organic Chemistry from Seoul National University (South Korea), working on biologically active peptide mimetics under the direction of Professor B. M. Kim. He then joined Professor Chung K.