There are many technological challenges of the twenty‐first century including energy, information, and transportation. During the continuous innovations, polycondensates have been supporting our modern life in the global society. The synthetic methodology of polycondensation allows for a wide variety of available monomers and polymer structures than any other synthetic polymerization technique, which are derived from almost infinite kinds of designing structures in monomers compared to vinyl monomers. In addition, the high performance of specially designed polycondensates (eg, high thermal, chemical, mechanical, and dimensional stability) have provided a breakthrough, especially in material science and industry, as represented by the developments of superengineering plastics, such as wholly aromatic polyamides, polyimides, poly(phenylene ether)s, poly(ether sulfone)s, poly(ether ketone)s, and poly(ether ether ketone)s. Polycondensation chemistry is also used for preparing recent optoelectronic applications including organic electroluminescence, field–effect transistors, organic solar cells, polymer memories, and so forth. This article, details the basic principles of polycondensation and recent advances in polycondensation.