Bioorthogonal chemistry developed from innovation in chemistry, can be applied to various fields of biology e.g. in emerging pathogen-host interaction, in cancer biology and medicine and in plant biology.The reactants of bioorthogonal chemistry reactions have the property of biocompatibility and does not interfere with any native biochemical processes in living cells. Chemically synthesized analogs of biomolecules tagged with azide as bioorthogonal reactants, may be metabolically incorporated into the cell's biosynthetic machinery, processed and destined into different locations of cells and finally probed with alkynes tagged with fluorescent molecules. Azides are very small molecules, absent in biological system and therefore azide-alkyne reaction is one of the ideal bioorthogonal reactions in living cells. These reactions are now being applied to various biochemical processes of the cells e.g., protein trafficking, nucleic acid dynamics, medicinal chemistry and in plant cell-wall biosynthesis, It is hoped, that in future, synthesis of many more new molecules and development of new bioorthogonal reactions will help to identify new unidentified biological reactions in the cells.