Size-based molecular sieving works well for rigid molecules with complete exclusion of larger ones, yet interaction-induced molecular sieving may offer unusual separation capability for molecules with matching physicochemical properties. Here we report a MOF material (XXU-3) featuring one-dimension channels with embedded molecular pockets opening to C3H6 and C3H8 at substantially different pressures. The dynamic nature of the pockets is revealed by single-crystal-to-single-crystal transformation upon exposure of the activated XXU-3 to C3H6 or C3H8 atmosphere. Breakthrough experiments demonstrate that XXU-3 is not only capable of separating C3H6 from C3H8 with record-high C3H6 productivity, but also the first MOF material realizing polymer-grade C3H6 production in a single adsorption-desorption cycle from an equimolar C3H6/C3H8 mixture. The underlying separation mechanism, namely orthogonal-array dynamic molecular sieving, is an exemplary strategy for both large separation capacity and fast adsorption-desorption kinetics. This work presents an ideal design for next-generation sieving materials and it holds great potential for applications in adsorptive separation.