Silylated 1,1,1-tris(4-hydroxyphenyl)ethane (THPE) was polycondensed in N-methylpyrrolidone with either 2,6-difluorobenzonitrile or 2,4-difluorobenzonitrile under conditions allowing for complete conversions of the C−F groups. With 1.0:1.0 stoichiometry, completely soluble polyethers were obtained from both isomeric difluorobenzonitriles. The MALDI−TOF mass spectra proved tree-shaped and cyclic polyethers to be the main products. With a molar excess of 10%, the 2,6-difluorobenzonitrile gave a cross-linked product at a concentration of 15 mmol/30 mL (THPE/NMP) or cross-linking occurred with 20 mol % excess at a concentration of 4 mmol/30 mL. However, the 2,4-difluoro isomer yielded soluble polyethers even in an excess of 50 mol %. Such an excess of the difluoro monomer had the consequence that linear and tree-shaped polyethers were never formed, and multicyclic oligomers or polymers became the predominant reaction products, so that even with ideal stoichiometry gelation did not occur. Multicycles free of f...