Five asphaltene samples from three different source types-immature source rock (ISA), petroleum (PA), and coal (CDA)-are studied using integrated chemical and spectroscopic techniques (elemental analysis, C-13 magnetic resonance spectroscopy, infrared spectroscopy, and X-ray spectroscopy) to understand their chemical compositions, molecular architectures, and structure-solubility relationships. The three asphaltene classes are found to have grossly different compositions, reflecting their source. ISA that have experienced little-to-no catagenesis have the highest aliphatic carbon content, lowest aromatic carbon content, and high polar heteroatom (sulfoxide-sulfur) content. PA from reservoir crude oils have higher aromatic carbon content and largely nonpolar heteroatom (thiophene-sulfur) content. CDA have the highest aromatic carbon content and low total sulfur content. Despite these compositional differences, all asphaltenes maintain the required strength of intermolecular interactions according to their solubility definition. However, the three types of asphaltenes are found to achieve the same intermolecular interaction in different ways. CDA have strong pi-pi stacking between their PAH cores with little steric disruption from aliphatic structures, indicating intermolecular interactions dominated by polarizability. PA also have strong pi-pi stacking but with enhanced disruption from their larger number and size of aliphatic structures on PAH clusters. Enhanced polarizability may exist in PA via dispersion forces due to the larger molecular weight of PA versus CDA. By comparison, ISA have relatively weak pi-pi stacking owing to their smaller PAH and increased steric disruption from abundant aliphatic carbon. This reduced strength of polarizability interactions in ISA is compensated by the presence of polar moieties (sulfoxide and carbonyl) that enhance dipole-dipole and/or dipole-induced dipole interactions. These interpretations are consistent with measured planarity of single asphaltene molecules and with molecular mechanics modeling of asphaltene nanoaggregate structures. These observations of same solubility yet different composition among asphaltene classes can be understood with respect to Hansen solubility parameters for which polarizability is the dominating force between asphaltene molecules.