alpha,omega-Bis(vinyldimethylsilyl)alkanes (1-4) of the general formula CH2 = CH(CH3)(2)Si(CH2)n-(CH3)(2)SiCH =CH2 (where n = 1-4) undergo effective silylative coupling (SC) polycondensation, if catalyzed by [RuCl2(PPh3)(3)] (II) or [RuHCl(CO)(PPh3)(3)] (III), giving linear polymers (5-8) (M,, = 7300-8500) containing a mixture of trans-1,2- and gem-fragments, but in the presence of [{RuCl2(CO)(3)}(2)] (1) as a catalyst, highly stereoselective trans-tactic linear polymers are isolated (9-12) (M-w = 6200-9200). The products of both new processes cannot be synthesized via ADMET polymerization or ring-closing metathesis (RCM).