The use of syntonic engineering (SE), or synthonic modelling has been increasing in the pharmaceutical industry. This study used the Material Studio and HABIT98 programs to model the intermolecular (synthonic) interactions, lattice energetics, and morphology prediction. Two organic systems representing common active ingredients and excipients were selected, Theophylline (TH) and D-mannitol (DM). The Nemethy and Dreiding force fields (FF) paired with matching semiempirical chargers were used for all SE calculations for all case studies. For both systems, hydrogen bonding OH…H was the dominating interaction. The interatomic stability for TH was mainly contributed by the amino nitrogen making amide the primary functional group. In DM, interatomic stability was attributed to the hydrogen atom, making hydroxyl the primary functional group. TH was crystallised as needle-like, while DM was dendritic.