PURPOSE: To obtain the subject new compound useful as a raw material for various high molecular materials such as coatings or adhesives or a constituent for curing compositions, and capable of giving polymers having excellent resistance to heat, chemicals and oil, etc.

CONSTITUTION: This new compound, acrylonitrile dimer of formula I, is obtained by reaction between acrylonitrile and formaldehyde in the presence of a tertiary amine at the charge molar ratio of pref. (6:40) to (10:90). The second objective acrylonitrile derivative can be obtained by reaction between acrylonitrile and formaldehyde in the presence of a tertiary amine at the charge molar ratio of (95:5) to (60:40). The third objective polymerizable composition containing ≥50mol% of the acrylonitrile dimer has improved heat resistance, while, another version of the polymerizable composition containing ≥50mol% of the acrylonitrile derivative and <20mol% of the acrylonitrile dimer has improved transparency.