A microporous material comprises organic macromolecules comprised of first generally planar species connected by rigid linkers having a point of contortion such that two adjacent first planar species connected by the linker are held in non-coplanar orientation, subject to the proviso that the first species are other than porphyrinic macrocycles. Materials in accordance with the invention have a surface area of at least 300 m.sup.2 g.sup.-1, eg in the range 700-1500 m.sup.2 g.sup.-1. Preferred points of contortion are spiro groups, bridged ring moieties and sterically congested single covalent bonds around which there is restricted rotation.