Transition metal (Pt-II or Pt-0) catalyzed ring-opening polymerization (ROP) of silicon-bridged [1]-ferrocenophanes has been found to permit simple and convenient control of the regiostructure, molecular weight, and architecture of poly(ferrocenes). Whereas thermal ROP of the unsymmetrical silicon-bridged [1]ferrocenophane Fe(eta-C5H4)(eta-C5Me4)SiMe2 (3) at 150 degrees C proceeds via a nonselective cleavage of the SiCpH and Si-Cp-Me bonds (Cp-H = eta-C5H4, Cp-Me = eta-C5Me4) to yield an amorphous, regioirregular poly(ferrocenylsilane), the Pt-catalyzed ROP of 3 in solution at 25 OC involves selective cleavage of the SiCpH bond to afford a crystalline poly(ferrocenylsilane) 5 with a regioregular microstructure. Regioselective ROP of 3 was also detected during the Pt-catalyzed copolymerization of 3 with benzosilacyclobutane (7), The presence of Et3SiH during the Pt-catalyzed ROP of the [1]silaferrocenophane Fe(eta-C5H4)(2)SiMe2 (1) permits molecular weight control and the formation of poly(ferrocenylsilanes) capped by Et3Si and Si-H groups, Et3Si-[Fe(eta-C5H4)(2)SiMe2](n)-H (11) with M-n = 2000-45 000 and PDIs of 1.1-2.3. The use of siloxane-based materials with Si-H groups such as the random copolymer [MeHSiO-/-Me2SiO](n) or the cyclotetrasiloxane [MeHSiO](4) in place of Et3SiH allowed the preparation of comb-shaped polysiloxane-poly (ferrocenylsilane) graft copolymers (12) and star-shaped polymers (16) with a cyclic siloxane core, respectively. In addition, the use of Si-H terminated poly(dimethylsiloxane)s in place of Et3SiH provided facile access to poly(ferrocene)poly(siloxane)-poly(ferrocene) triblock copolymers (18).