Thioether containing polyimides were prepared by displacement of chlorine groups from substituted imides by aromatic and aliphatic sulfur nucleophiles. The all-aromatic monomers and polymers had poor solubility which led to precipitation during synthesis and low molecular weight polymers. However, these polymers were thermally stable up to 400 degrees C and had T-g’s ranging from 212 degrees C to 233 degrees C. Poly(thioether imide)s prepared from 1,3-propanedithiol and 2-mercaptoethyl sulfide had good solubility but lower thermal stability, showing TGA loss onset temperatures of 297 degrees C and 298 degrees C, respectively.