Polycyclotrimerization and polycoupling of acetylenic monomers respectively furnish hyperbranched polyarylenes and polyynes with high molecular weights (up to 1 #61620; 106) in high yields (up to 99.9%). The polymers possess low intrinsic viscosities and high thermal stabilities

losing little of their weights when heated to 400℃. Upon pyrolysis at 800℃

the polymers graphitize with high char yields (up to 86%). Hyperbranched polyarylenes efficiently emit deep-blue to blue-green lights with fluorescence quantum yields up to 98% and strongly attenuate intense laser pulses with optical power-limiting performances superior to that of C60

a well-known optical limiter. Poly(alkenephenylenes)

poly(aroylarylenes) and polyynes are readily cross-linkable by UV irradiation

serving as excellent photoresist materials for the generation of patterns with nanometer resolution. Thin films of hyperbranched polyynes exhibit very high refractive indexes (n up to 1.86). The internal and terminal acetylene moieties of the polyynes readily form complexes with cobalt carbonyls

which can be transformed into soft ferromagnetic ceramics with high magnetic susceptibilities (Ms up to ca.118 emu/g) and near-zero magnetic losses.