Three aliphatic molecules and their subsequently formed protonated congeners are considered as representatives of the macrocyclic polyamines (azacrowns) and related polyammonium salts. Important methodological aspects of structural investigations on these highly mobile aza-substituted macrorings are taken into account, especially concerning aqueous solutions over a whole pH range. This book examines various issues about ascertaining donating sites and sequences of the protonation, dynamics and conformational preferences of such multidentate polyamino ligands as potential chelators (complexones) are considered.