It has been shown by UV-vis spectrophotometric method that p-bromanil forms inclusion complex of 1:2 stoichiometry with coal-derived asphaltenes. The absorption peak for the complex has been detected by difference spectral method and has been compared with those for complexes involving chloranils. The wavelengths of the maximum absorption are in the expected order of electron affinities of the chloranils and bromanil. The formation constants (K) have been determined using the Benesi-Hildebrand equation. The magnitudes of K are large compared to those of weak charge transfer complexes (for which K approximate to 10(1) to 10(3) dm(3) mol(-1)) but are comparable to those of some recently reported supramolecular or inclusion complexes. The study reveals the presence of pi-donor (i.e., aromatic) type of groups in asphaltene molecule. It also supports the view that bromanil molecules get included into structures provided by asphaltene molecules. Thermodynamic parameters Delta H-0 sand Delta S-0 for the complexation process have also been determined.