The solid‐state structures of two polymorphs and two alcoholates (ethanol and isopropanol) of formoterol fumarate have been investigated by a combination of NMR techniques. First‐principles shielding computations are combined with NMR data to successfully relate peaks to their crystallographic positions for the solvates, including atoms that are in equivalent molecular positions. The uncharacterised structure of the asolvate form C is found to contain a single formoterol ion and half a fumarate ion in its asymmetric unit. HETCOR experiments for the ethanolate and form C allow proton chemical shifts to be determined and give improved 13C resolution for the former compound. Desolvation of the solvates to form C has been monitored under the conditions of the NMR experiment. Differential rates of phenylene ring flipping are observed in the different forms. Carbon‐13 relaxation times and 2H NMR are used to probe dynamics of the fumarate ion. Copyright © 2012 John Wiley & Sons, Ltd.