Variable-temperature C-13 NMR T-1 and NOE measurements were performed on alkyl-substituted oligo(phenylenevinylene) (OPV) melts at two Larmor frequencies. The existence of a liquid crystalline (LC) phase in OPV was demonstrated by DSC and polarized microscopy experiments. The NMR data showed that while the OPV backbone behaves like a liquid crystal, the side chains act merely as a "solvent". The backbone C-13 T-1 data were fitted to a modified log chi(2) distribution, and information regarding backbone rotational dynamics was extracted from the fitting. It was found that the backbone rotational dynamics slow down as the OPV sample crosses from the LC phase into the isotropic phase. Instead of a sharp transition, the OPV LC-isotropic phase transition occurs in a temperature window of 2-3 degrees C. The composition of the two phases in the biphasic region was also calculated from the T-1 data as a function of temperature.