A simplified model of the PDI-Pyrene heterodimer was created from the polymer subunits, with a dimer configuration as closely resembling the experimental structure as possible. From renderings of the full structure, we observe an H-type aggregate dimer as per Kasha's paradigm rotated along a Z-axis by approximately 55°. The optimized geometries for the electronic ground and first singlet excited states for both the PDI and pyrene subunits were obtained using the Becke 3-parameter Lee-Yang-Parr (B3LYP) hybrid density functional and the correlation-consistent double-ζ valence polarized cc-pVDZ basis set. The dimer excited state was created using the S1 state of PDI and the S0 state of pyrene.