Temperature dependence of the self-assembly of deoxyguanosine 5'-monophosphate in pretransitional region of the I-Ch phase transition was investigated by dynamic light scattering. Measurements reveal the presence of two diffusive modes: the slower mode is attributed to the motion of large globular aggregates, white the faster mode is related to the translational motion of the self-assembled columnar stacks. By increasing temperature the number of assembled molecules decreases, as seen from a reduction in the fast mode amplitude, until this mode finally disappears. Dynamical behavior of the slow diffusive mode is more complex and coupled to the dynamics of the fast mode.