Among the contingency of methodologies available for bioconjugation, the Click dipolar [3+2] cycloaddition pathway
that results in the formation of triazole linkage were extensively investigated during the last few years in a wide variety of molecular architectures
– that ranges between small molecules and polymers. Synthetic feasibility as well as the stability and application of triazole
linkage were explored and successfully accomplished in live cells, in vitro, in vivo and tissues. The objective of this review is to present
recent reports of this synthetic methodology, as applied to oligonucleotide chemistry. Advances in development of Click solid supports,
newer alkyne and azide building blocks, covalent conjugations at either termini (3',5'), internal sites (base, sugar and backbone), solid
and solution-phase labeling strategies, and applications to oligonucleotide detection are summarized in this review.