Mg-ptcda (ptcda = perylene-3,4,9,10-tetracarboxylic dianhydride) coordination polymer particles (CPPs) with special hexagonal tubes morphology were manufactured by a self-assembly and hydrothermal method. The growth process from unstable nanoribbons to metastable hexagonal rods to a core–shell structure and finally to the stable hexagonal tubes was achieved and investigated by SEM and XRD characterizations. The morphology of Mg-ptcda is mainly controlled by Ostwald ripening and self-templating mechanism. Mg-ptcda CPPs with various morphologies, such as hexagonal rings and snowflakes, and particle sizes from micro to nanoscale can be finely tuned using organic solvent as additives. The optical properties of Mg-ptcda CPPs show that incorporation of ptcda dyes in coordination polymers can efficiently reduce their aggregation and interaction in the solid state. Furthermore, porous MgO nanomaterials with various morphologies can be fabricated from Mg-ptcda CPP precursors by a simple thermal treatment process.