Miscibility maps for blends of copolycarbonates based on various proportions of tetramethyl bisphenol-A and bisphenol-A (TMPC-PC) with copolymers of styrene-maleic anhydride (SMA) have been established and interaction energies have been calculated from the data using a binary interaction model combined with the Flory-Huggins theory. This analysis provides an independent assessment of all six interaction energies between the various repeat unit pairs. These include the first reported estimates for the binary interaction energies of MA with TMPC and with PC. The other four interaction energy values found here are in excellent agreement with earlier reports. LCST-type phase separation temperatures were determined and compared with values predicted by the Sanchez-Lacombe equation-of-state theory.