Carbon-13 nuclear spin relaxation in 1,8-bis(dimethylamino)naphthalene (DMAN) was investigated in a dimethylformamide-d(7) solution. In addition, the chemical shielding tensors were measured in the crystalline powder. Detailed analysis of C-13 longitudinal relaxation in this molecule yielded its rotational diffusion tensor. Comparison to the protonated form of DMAN, DMANH(+), leads to conclusions concerning interaction of the latter with its counterion.