Abstract The use of TOSS spinning sideband suppression to obtain 13C n.m.r. spectra of a wide range of aromatic materials is discussed in relation to the spectra of the same materials obtained without sideband suppression. The 39 samples studied include polymers containing both aromatic and aliphatic carbon, asphaltenes, fossil fuels spanning the range in rank from pet to semianthracite, pitch, separated macerals, laboratory oxidized coals and naturally weathered, stockpiled bituminous coals. Despite the diversity in structure, it is found that sideband suppression can be used to obtain apparent aromaticity values consistent with the normal spectra in the majority of samples. The observation of inaccurate aromaticities due to destructive interference between the frequencies associated with magic angle spinning and slow molecular motions in some samples is illustrated.