Poly(diaza-3n-crown-n)s having hydroxyethyl side arms (PDC(n)s : n = 5-7) were prepared, and their effects on the ionic conductivity of both inorganic salts and cation conductive polymers were analysed. A series of alkali metal perchlorates (MClO(4), : M = Li, Na, K, Rb, and Cs) were mixed with the PDCn materials. However, although ionic conductivity better than 10(-6) S cm(-1) above 60 degrees C was achieved, no effect was seen of any specific coupling of the cation and the crown cavity size on the ionic conductivity. This was probably due to the contribution of the anion conduction. In order to neglect the effect of anion migration, cation conductive polymers were mixed with the PDCn materials. K+ and Na+ showed the lowest ionic conductivity in PDC6 and PDC5, respectively, reflecting stronger interactions with crown ethers having more suitable cavity sizes. The presence of crown ether units in the polymer was also suggested as being responsible for accelerating the dissociation of salts with cations which were smaller than the size of the crown ether cavity,