Diamine 3,3-bis[4-(4-aminophenoxy)-3-methylphenyl]phthalide (BAMP) was derived from the o-cresolphthalein, and then it was polycondensated with various aromatic dicarboxylic acids and dianhydrides to synthesize polyamides (PAs) and polyimides (PIs), respectively. PAs have inherent viscosities of 0.78-2.24 dL/g. Most of the PAs are readily soluble in a variety of solvents such as DMF, DMAc, and NMP and afforded transparent and tough films from DMAc solutions. The cast films have tensile strengths of 75-113 MPa as well as initial moduli of 1.71-2.97 GPa. These PAs have glass transition temperatures (T(g)s) in the range of 242-325 degrees C, 10% weight loss temperatures occur up to 473 degrees C, and char yields are between 57 and 64% at 800 degrees C in nitrogen. PIs were first synthesized to form polyamic acids (PAAs) by a two-stage procedure that included a ring-opening reaction, followed by thermal or chemical conversion to polyimides. Inherent viscosities of PAAs are between 0.71 and 1.63 dL/g. Most of the PIs obtained through the chemical cyclodehydration procedure are soluble in NMP, o-chlorophenol, m-cresol, etc., and they have inherent viscosities of 0.58-1.32 dL/g. T(g)s of these PIs are in the range of 270-305 degrees C and show 10% weight loss temperatures up to 477 degrees C. PIs obtained through the thermal cyclodehydration procedure have tensile strengths of 72-142 MPa, elongations at break of 8-19%, and initial moduli of 1.80-2.72 GPa.