As there were two types of patchy interactions leading to attractive interactions between windows, and windows and arenes, there are two interaction strengths to consider for J in Equation. 3. These are referred to as J ww and J wa for the interaction between the orange and blue patches, and green and blue patches as shown in Figure . 6. As the absolute energy scale is not important to the results of this study, for simplicity the interaction strengths were chosen for the simulation such that the transition temperature T t in which a cluster forms occurs when k B T t ≈ 1 for the dominant interaction between the windows, which occurred when J ww = 60. J wa was chosen to be smaller than J ww , such that without the interactions that favoured window-to-window packing, the cluster would form with windowto-arene packing as the dominant motif at k B T t ≈ 0.75, resulting in a value of J wa = 15.