The crystal structure of two semiflexible dicarboxylic acids forming chains
is reported; these compounds are models for the crystal packing of polyest
ers based on 1,5- or 2,7-dihydroxynaphthalene and aliphatic dicarboxilic ac
ids and, more generally, for crystal packing of semiflexible chains contain
ing conformationally blocked aromatic cores along the chain. In both crysta
l structures, chain axes are not parallel to each other, this unusual featu
re being connected, seemingly, with the lateral packing of aromatic cores p
resent in the molecules.