Aromaticity is an important property of many petroleum derived streams. Traditional thermodynamics tools (e.g., cubic equations of state) do not provide any special treatment to these aromatic hydrocarbons. A feature which discriminates aromatics from paraffins is that aromatic rings exhibit anisotropic pi-pi interactions. Accounting for this key difference between aromatic and non-aromatic hydrocarbons in an equation of state will allow for a level of predictability which is not possible with our current tools. By mapping the anisotropy of pi-pi attractions onto a dipolar free energy, we develop a simple and powerful treatment of aromatic hydrocarbons within the PC-SAFT equation state. We demonstrate that this approach provides a substantial increase in performance over the standard non-polar treatment of aromatic molecules. The methodology developed is used to develop a generalized hydrocarbon model in instalment II of this series. (C) 2019 Elsevier B.V. All rights reserved.