Condensation of fluoro-substituted and silyl-substituted monomers provides polymers suitable for use, e.g., as engineering polymers. A monomer composition is condensed in the presence of a basic catalyst. The monomer composition contains a compound of formula F—X—F and a compound of formula (R1)3Si—Z—Si(R1)3, and forms an alternating X—Z polymer chain and a silyl fluoride byproduct. X has the formula -A(-R2-A)n-; each A is SO2, C(═O) or Het; R2 is an organic moiety; n is 0 or 1; Het is an aromatic nitrogen heterocycle; Z has the formula -L-R3-L-; each L is O, S, or N(R4); and each R3 is an organic moiety, and R4 comprises H or an organic moiety.