The phase diagram of blends of liquid crystalline polymer (LCP) and polycarbonate (PC) was constructed. The effect of temperature on morphological development in melt-blended samples was examined with a polarized light microscope, in conjunction with a heating stage. Phase separation in the blend was observed as the temperature was increased. For a particular LCP/PC blend composition, two-phase separation temperatures (T-sp1 and T-sp2) were determined. Consequently, the corresponding phase diagram relating to phase separation was constructed. It was divided into three regions. No phase separation occurred when the blend was below T-sp1. However, a slight phase separation was detected when, the temperature was between T-sp1 and T-sp2. Moreover, pronounced phase separation was observed when the blend was at a temperature above T-sp2. The phase-separated structure varied according to the initial composition of the blends. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 396407, 2009