One of the two fundamental requirements of a practicing organic chemist is the capability to transform one functional group into another, with the other being the ability to establish carbon-carbon bonds. Almost every synthesis of organic compounds necessitates, at some point in the process, the interconversion of at least one functional group. In this regard, we have provided examples of reactions involving major functional groups in organic chemistry, such as alkenes, halides, alcohols, and carbonyl compounds, categorized under headings that provide insight into the type of reaction.