AbstractPolymers containing 1‐trifluoromethylvinylene, 1,4‐phenylene, and/or 2,5‐thiophenediyl units (6a,band8a‐d), obtained by base‐free Wittig condensation reactions with phase transfer catalysts, were investigated combining direct evaporation in the ion source of a double focusing mass spectrometer with the “Linked‐Scan” metastable technique. This method could be shown to allow the unequivocal identification and differentiation of components in polymers up to high mass regions (m/z≤ 3000). The degree of polycondensation up to 18 aromatic/heteroaromatic units in the chain was determined by mass chromatography, which correlated with the HPLC results. Terminal groups and sequence ions were characterized by comparison of metastable transitions of selected ions with model compounds. Detailed information on the polycondensation reaction was obtained. In addition to linear products, cyclic species with 3 to 18 arylene‐1‐trifluoromethylvinylene units were formed. The main fragmentations may be explained by sterical effects of both the α‐trifluoromethylstilbene moiety and the heteroaromatic analogues