Efficient exciton diffusion is a necessary feature for light-harvesting systems in high-performance organic photovoltaic devices. In this work, a combination of electronic structure methods, crystallographic information, and an exciton diffusion model is used to assess the efficiency of exciton diffusion in a set of benzodiindolizine derivatives crystals. The method employed here takes into account the effects produced by variations in intermolecular distances and relative orientations that stem from the different crystalline arrangements observed for each derivative. Results show the highly anisotropic nature of exciton diffusion in these crystals, which is demonstrated to be mainly one dimensional for most compounds. This is partly responsible for the large estimates of exciton diffusion length obtained for these crystals, showing their significant potential for applications that are dependent on efficient exciton diffusion such as organic photovoltaics. We conclude that the choice of solubilizing groups drastically changes the expected exciton diffusion length and the anisotropy degree of the diffusion process, which makes the judicial choice of such groups an important strategy in the rational design of organic photovoltaic devices.