Dendritic–linear–dendritic triblock copolymers based on poly(ethylene glycol) (PEG) as the core and dendritic triazine blocks were synthesized. The micellar and aggregation characteristics of the compounds were investigated with NMR and fluorescence spectroscopy. The NMR investigations were carried out in a variety of solvents. In those solvents in which both moieties of the linear–dendritic compounds were completely soluble, the NMR spectra of the linear–dendritic compounds were in the normal form, and all of the signals were as expected. However, in other solvents in which one of the moieties of the compounds was not very soluble, the NMR spectra of the compounds were not in the normal form, and some of the signals were broad or disappeared. The results could be related to the aggregation behavior of the block copolymers with extended or packed conformations of PEG in the solvents, as previously observed in similar systems. Also, fluorescence investigations of some of the isolated compounds in aqueous solutions displayed micellar behavior. The critical micelle concentrations of the copolymers were determined with a fluorescence technique.