While the breakdown of the quadrupolar electrostatics picture is unambiguous, and the alternative vdW model has been demonstrated to drive offsetstacking in a variety cases, the role of substituents has not yet been examined as it pertains to paralleldisplaced π-stacking. That aspect is addressed herein by examining substituted aromatic dimers including heterocycles, which have enhanced electrostatic interactions as compared to the unsubstituted benzene dimer. Our interest lies not in the effect of substituents on the stacking energies, which has been addressed comprehensively by Wheeler and Houk, but rather on the origins of offset-stacking. That was the original consideration leading to fixation on quadrupolar electrostatics, 2,29,52 and elucidating the fundamental driving forces behind offset-stacking has implications for much larger systems including covalent organic frameworks. There, slip-stacking may occlude the pores and stymie catalytic applications. In other cases, offset-stacking in may enhance electrical conductivity and/or exciton delocalization, yet conductivity is exquisitely sensitive to the interlayer spacing. For these reasons, it is important to know whether offset-stacking behavior is be tunable by addition of electron donating or withdrawing groups.