Bisphenol A (BPA) carbonate cyclic oligomers have been found to be miscible with a wide spectrum of glassy polymers from polystyrene to aromatic polysulfones. The surprising breadth of the cohesive energy density (CED) range corresponding to this spectrum is roughly comparable to the breadth of the CED range of small molecule solvents that swell a given glassy polymer heavily, and much smaller than the breadth of the CED range of miscibility seen in a polymer/polymer blend series. Possible sources of this behaviour are indicated.