We report the development of a novel double layered photoanode for dye sensitized solar cells made of highly crystalline TiO₂ octahedral nanocrystals and agglutinated mesoporous TiO₂ microspheres. The underlayer of nanooctahedra serves as a transparent photoanode for copious and strong dye adsorption on the smooth (101) surfaces and for facilitated electron transport. Although the nanooctahedra are extremely small, our synthetic route has ensured a well-faceted crystalline shape with sharp edges and smooth surfaces, resulting in a 7.61% power conversion efficiency, much higher than that of P25 (5.76%). Separately, the overlayer of hierarchical TiO₂ mesoporous microspheres plays the multiple roles of efficient light scattering, dye absorption and electrolyte permeation. Especially noteworthy is the agglutination of the microspheres through our 3D necking process, which has yielded an electron diffusion coefficient five times that of the P25 network and four times that of the nanooctahedra network. This is a significant breakthrough in DSSCs, which ensures that the photogenerated electrons in the overlayer can be effectively transported through such highway-like paths and ultimately collected at the FTO electrode. Therefore, in this double layered photoanode we have taken into consideration a number of disparate factors aimed at enhancing the overall DSSC performance. Drawing on the judicious combination of materials synthesis and engineering of nano-architectures and interfaces, solar cells based on this double layered structure have achieved 8.72% power conversion efficiency even with simple device fabrication procedures, showing promise as a new photoanode design for high efficiency dye sensitized solar cells.