Poly(1,4-(1-phenylbutadiene)) (poly1BP) and poly(1,4-(1-biphenylylbutadiene)) (poly1BPB) polymerized anionically in tetrahydrofuran (THF) have microstructures of 90.9 and 96.4% of 1,4 units, and 9.1 and 3.6% of 3,4 units, respectively, as determined by 400 MHz H-1 NMR. However, poly(1,4-(1-naphthylbutadiene)) (poly1NB) and poly(1,4-(1-phenanthrylbutadiene)) (poly1PAB) have 1,4 structures only. The C-13 NMR spectra of the alternating copolymers of arylethylenes and ethylene obtained by hydrogenation of the poly(1,4-(1-arylbutadienes)) show a fine structure that can be attributed to dyad or triad stereosequences. These spectra indicate that the alternating (arylethylene/ethylene) copolymers prepared from poly1BPB, poly1NB, and poly1PAB slightly favor isotactic structures.