The present article comprehensively reviews the macromolecular synthesis using enzymes as catalysts. Among the six main classes of enzymes, the three classes, oxidoreductases, transferases, and hydrolases, have been employed as catalysts for the in vitro macromolecular synthesis and modification reactions. Appropriate design of reaction including monomer and enzyme catalyst produces macromolecules with precisely controlled structure, similarly as in vivo enzymatic reactions. The reaction controls the product structure with respect to substrate selectivity, chemo-selectivity, regio-selectivity, stereoselectivity, and choro-selectivity. Oxidoreductases catalyze various oxidation polymerizations of aromatic compounds as well as vinyl polymerizations. Transferases are effective catalysts for producing polysaccharide having a variety of structure and polyesters. Hydrolases catalyzing the bond-cleaving of macromolecules in vivo, catalyze the reverse reaction for bond forming in vitro to give various polysaccharides and functionalized polyesters. The enzymatic polymerizations allowed the first in vitro synthesis of natural polysaccharides having complicated structures like cellulose, amylose, xylan, chitin, hyaluronan, and chondroitin. These polymerizations are "green" with several respects; nontoxicity of enzyme, high catalyst efficiency, selective reactions under mild conditions using green solvents and renewable starting materials, and producing minimal byproducts. Thus, the enzymatic polymerization is desirable for the environment and contributes to "green polymer chemistry" for maintaining sustainable society.

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Catalytic carbonylative C-H cyclization of 2-arylphenols can be achieved in the presence of a ruthenium-based catalytic system. The process proceeds efficiently under balloon pressure of CO and produces variously substituted 6H-dibenzo[b,d]pyran-6-one compounds, typically in good to high yields. Functional groups such as the alkoxycarbonyl and acetyl groups as well as halogen atoms (F, Cl, and Br) are well tolerated during the reaction.

A review of the fabrication of polysaccharide ion gels with ionic liquids is presented. From various polysaccharides, the corresponding ion gels were fabricated through the dissolution with ionic liquids. As ionic liquids, in the most cases, 1-butyl-3-methylimidazolium chloride has been used, whereas 1-allyl-3methylimidazolium acetate was specifically used for chitin. The resulting ion gels have been characterized by suitable analytical measurements. Characterization of a pregel state by viscoelastic measurement provided the molecular weight information. Furthermore, the polysaccharide ion gels have been converted into value-added sustainable materials by appropriate procedures, such as exchange with other disperse media and regeneration.