Abstract: An improved method for the preparation of 24-crown-8 is described. Cyclization at room temperature and purification of the crude product via an acetonitrile complex provides a much higher yield than those reported in the literature. ... Because of their unique cation complexation properties, macrocyclic pol yethers ... (crown ethers) find applications in many different scientific areas.' The preparation ... Despite such synthetic difficulties, applications of 24-crown-8 ...