In this work, the first direct measurement of inter and intra-layer molecular self-diffusion in the smectic phases of a chiral smectogen (S)-2-methylbutyl-[4'-(4 ''-heptyloxyphenyl)-benzoyl-4-oxy-(S)-2-((S)-2')benzoyl)-propionyl)]-pro pionate (ZLL7/*) by means of pulsed field gradient NMR is reported. Self-diffusion coefficients as low as 10(-13) m(2) s(-1) have been measured by combining magic echo spin decoupling with a stimulated echo sequence. The transitions among synclinic-anticlinic smectic phases are associated with a change in the self-diffusion coefficients.