A series of low band gap poly(3-dodecylthienylenevinylene) (PTV) with controlled morphological order have been synthesized and blended with the electron acceptor [6,6]–phenyl-C61-butyric acid methyl ester (PCBM) for organic photovoltaic devices. Two polymers with the most and least side chain regioregularity were chosen in this work, namely the PTV010 and PTV55, respectively. Using photoluminescence, photo-induced absorption spectroscopy, and atomic force microscopy, we find no direct evidence of photoinduced charge transfer between the two constituents, independent of the bulk-heterojunction morphology of the film, although the possibility of formation of P+/C60− charge transfer complex was not completely ruled out. The large exciton binding energy (Eb = 0.6 eV) in PTV inhibits the photoinduced electron transfer from PTV to PCBM. In addition, excitons formed on polymer chains suffer ultrafast (<ps) intrachain decay to the dark 2Ag state in both PTV010 and PTV55 cases, whereas excitons generated on PCBM molecules undergo energy transfer only to PTV55 in the blend film. Thus, the addition of PCBM increases the photoluminescence yield with respect to neat polymer yield. The efficiency of the energy transfer process is shown to depend on the degree of polymer and PCBM intermixing within the film, which in turn is governed by the polymer chain orders. The effect of such intermixing on the resulting kinetics of photo-induced excitations is also discussed. Our results show limited effect of polymer crystallinity of PTV to its excitonic properties, much the contrary of the case with poly (3-hexylthiophene) which has similar chemical structure with PTV.