For the structural determination of a ligand bound to an amorphous macromolecular system, solid-state NMR can be Used to provide interatomic distances. It is shown here that selective labeling in discrete locations with tritium enables accurate measurement of long-range distances owing to the high gyromagnetic ratio of this nucleus without structural modification of the molecule. This approach gives access to the largest NMR distance ever measured between two nuclei (14.4 angstrom). H-3 MAS NMR appears to be a promising tool for structural applications in the biological and material sciences.