Different phenyl derivatives of dihydropyrrolopyrrolediones (DPP) have been examined by means of polarized absorption and fluorescence spectroscopy. The derivatives were 3,6-bis(3,5-di-tert-butylphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (BDPP), 3,6-bis(2-methoxyphenyl)-2,5-dimethylpyrrolo[3,4-c]pyrrole-1,4-dione (MHDPP),3,6-bis(2-methoxyphenyl)-2-hydro-5-methylpyrrolo[3,4-c]pyrrole-1,4-dione (MHDPP) and 3,6-bis(2-methoxyphenyl)-2,5-dihydropyrrolo[3,4-c]pyrrole-l,4-dione (HHDPP). Intramolecular hydrogen bonds can form between the DPP core and the phenyl groups of MHDPP and HHDPP. The Stokes shift (ca. 10-70 nm) and the bandshape of absorption and fluorescence spectra depend strongly on possibilities of intramolecular pi-electronic overlapping of the DPP core and the phenyl groups. Different conformations of the DPP and aryl planes are likely present. The rate of transfer between these conformations is rapid, which is supported by the monoexponential photophysics observed for all derivatives. The Lifetime varies between 5.5 and 9 ns in different liquid solvents, as well as in a lyotropic nematic Liquid crystal. The fluorescence quantum yields and Forster radii are reported. The wavelength dependence of the limiting fluorescence excitation and emission anisotropies have been studied. Except from MMDPP and MHDPP, the S-0 <-> S-1 bands constitute one direction of the transition dipoles corresponding to the same limiting anisotropy of r(0) = 0.38. Second rank order parameters of the ground and excited state were determined for the DPP derivatives solubilized in a macroscopically aligned lyotropic nematic liquid crystal. Taken together, the experimental results suggest that the molecular symmetry of HHDPP is the same in the ground and the first excited states, contrary to the other derivatives.