High-molecular compounds comprising repeating units represented by the general formula (1) or (2) and having number-average molecular weights of 103 to 108 in terms of
polystyrene: (1) [wherein Ar1 and Ar2 are each independently a trivalent
aromatic hydrocarbon group or a trivalent heterocyclic group; and X1 and X2 are each independently O, S, C(═O), S(═O), SO2, C(R1)(R2), Si(R3)(R4), N(R5), B(R6), P(R7), or P(═O)(R8), with the provisos that X1 and X2 must not be the same and that X1 and Ar2 are bonded respectively to the adjacent carbon atoms constituting the aromatic ring of Ar1, and X2 and Ar1 are bonded respectively to the adjacent carbon atoms constituting the aromatic ring of Ar2] (2) [wherein Ar3 and Ar4 are each independently a trivalent
aromatic hydrocarbon group or a trivalent heterocyclic group; and X3 and X4 are each independently N, B, P, C(R9), or Si(R10), with the provisos that X3 and X4 must not be the same and that X3 and Ar4 are bonded respectively to the adjacent carbon atoms constituting the aromatic ring of Ar3, and X4 and Ar3 are bonded respectively to the adjacent carbon atoms constituting the aromatic ring of Ar4].