To obtain a film-forming composition having excellent coating performance and useful for electronic parts, insulation film, etc., by including an organic solvent and a polyphenylene derivative obtained by the reaction of a specific biscyclopentadienone derivative with a diacetylene derivative.

The objective composition contains (A) a polymer produced by reacting a compound of formula I [R1 to R6 are each H, an alkyl or an aryl; X is a bivalent organic group of formula II (R7 is an alkyl or the like; (m) is 0-4) or the like] [e.g. 3,3'-(1,4-phenylene)-bis(2,4,5-triphenylpentadienone)] with a compound of formula A-C≡C-Z-C≡C-A {A is H, an aryl or the like; Z is group of formula Q-(Y)t-Q [Y is O or the like; (t) is 0 or 1; Q is a (substituted)arylenel, formula IV (D is O or the like; R12 is an alkyl or the like; (r) is 0-2) or the like} (e.g. 1,3-diethynylbenzene) and (B) an organic solvent (e.g. cyclohexanone).