A poly-phenylenevinylene derivative (poly (2,5-dioctyloxy)-p-phenylene vinylene) (DOO-PPV) with a high degree of physical crosslinking (designated the gelation of DOO-PPV) was synthesized and characterized. Analyses of the Fourier transform-infrared (FT-IR) and the Fourier transform-Raman (FT-Raman) spectra indicate that the chemical structure of the gelation of DOO-PPV is accordant with short chain linear molecule of DOO-PPV. Photoluminescence spectra of a thin film, short chain linear molecule, and solid gelation show that the ratio of the intensity at the short wavelength emitting band and at the long wavelength emitting band decreases gradually, the ratio is 3.24, 1.10 and 0.47, respectively. Analysis of X-ray diffraction (XRD) indicated that the existence of a more oriented structure in the gelation of DOO-PPV compared with the short chain molecule and the thin film. This result suggests that interchain and self intrachain aggregations play an important role in the photoluminescence.