The polyarylenes synthesized from polycyclotrimerization usually possess a hyperbranched
structure, which can be facilely assembled into fine morphologies. For example, TPE-containing
tetrayne 34 can be polymerized into poly(tetraphenylethene) (PTPE) 35 using TaCl5 as catalyst
(Scheme 5A) [44]. This A4-type monomer renders the resulting polyarylene a highly cross-linked
structure but with a good solubility. Abundant terminal groups and binding sites along the polymer
skeleton make the polymer to function as fluorescent chemosensor for explosives with
superamplification effect and large quenching constant. Hyperbranched PTPE can also be
prepared from A2-type monomer such as 12 (36c) under similar reaction conditions. Further
research found that indium chloride was an efficient catalyst for synthesizing regioregular
hyperbranched polymers (Scheme 5A) [45]. The resulting PTPE 37c contains only 1,3,5-
trisubstituted benzene linkages, suggesting that it possesses a good regularity.