PURPOSE: To provide the title polymer having excellent heat resistance, moldability, adhesion and moisture resistance, by reacting a specific 3,5- dialkylidenepyromellitide-1,7-dithione compd. with a diamine having an ether bond.

CONSTITUTION: 1.0mol. of a 3,5-dialkylidenepyromellitide-1,7-dithione compd. of formula I (wherein R7W8 are each H, lower alkyl or a group of formula II) is reacted with 0.95W1.05mol. of a diamine having an ether bond and represented by formula III (wherein R1W4 are each H, lower alkyl, lower alkoxy, Cl, or Br; R5W6 are each H, methyl, ethyl, trifluoromethyl, or trichloromethyl) in a solvent in the presence of a dehydrating agent at 10°C or below for a period of at least 4hr to prepare an arom. polyether-imidine having recurring units of formula IV (wherein A is a group of formula V).