Provided is a curable composition having excellent workability and being capable of forming a cured product having excellent heat resistance. The curable composition of the present invention includes a compound represented by Formula (1) below and a solvent: In Formula (1) below, R1 and R2 each represent a curable functional group, and D1 and D2 each represent a single bond or a linking group. L represents a divalent group having a repeating unit containing a structure represented by Formula (I) below and a structure represented by Formula (II) below. In Formula (I) and Formula (II) below, Ar1 to Ar3 each represent a group in which two hydrogen atoms are removed from an aromatic ring structure or a group in which two hydrogen atoms are removed from a structure in which two or more aromatic rings are bonded through a single bond or a linking group. X represents —CO—, —S—, or —SO2—, and Y represents —S—, —SO2—, —O—, —CO—, —COO—, or —CONH—. n represents an integer of 0 or greater.