1,12-Dihydroxydodecane and 1,22-dihydroxydocosane were prepared from diacetylene precursors in such a way that the four central methylene groups were deuterated. These deuterated spacers were polycondensed with the acid chloride of N-(4＇-carboxyphenyl)trimellitimide. Analogous poly(esterimide)s were prepared from fully protonated spacers. Furthermore, copolyesters were synthesized from a 1/1 mixture of 1,12-dihydroxydodecane and 1,22-dihydroxydocosane, one of which contained a deuterated dodecane spacer, whereas in the analogous polyester the docosane spacer is deuterated. All poly(ester-imide)s were subjected to a thermal treatment yielding a smectic-E phase in the solid state. C-13 nuclear magnetic resonance (n.m.r.) cross polarization magic angle spinning CP/MAS spectra revealed that spacers with greater than or equal to 12 methylene groups contain trans-trans conformations even up to 100 degrees C. H-2 n.m.r. spectroscopic measurement revealed that the spacers are nearly immobile at - 180 degrees C, but gain increasing mobility upon heating. Whereas the central segments of the docosane spacer can perform crank-shaft motions at ambient temperature? the motion of the dodecane spacer is restricted to kinks. At 100 degrees C the middle segments of the spacers partly are capable of isotropic motion in the solid smectic-E phase.