A series of poly(ferrocenyldimethylsilanes) (PFS) with narrow molar mass distribution were prepared via anionic ring-opening polymerization. The thermal behavior and morphology of these materials were investigated. Differential scanning calorimetry (DSC) experiments showed multiple melting endotherms upon heating after isothermal crystallization. Melting of thin lamellae and recrystallization into thicker lamellae accounted for these multiple transitions. Wide-angle X-ray scattering (WAXS) showed that the crystal structure remained unchanged during heating. An increase in the long-period observed with temperature-dependent small-angle X-ray scattering (SAXS) supported the assumption that lamellar thickening occurs. The semicrystalline polymers showed a melting behavior as described by the Hoffman-Weeks equation, leading to an equilibrium melting temperature of 143 degrees C.