Poly (glycidyl methacrylate) (PGMA) was successfully synthesized and proposed as a novel phase separator for fabrication of macroporous crosslinked poly (glycidyl methacrylate-co-ethylene dimethacrylate) (poly (GMA-co-EDMA)) monoliths with well-defined three dimensional (3D) skeletal structure. The ratio of PGMA in porogenic system had significant influence on morphology development of the monolith. To gain insight into the effect of PGMA chain length on morphology formation, PGMA homopolymers with different molecular weights were further synthesized for monolith preparation. Porous structure of the monoliths was characterized by scanning electron microscope, mercury intrusion porosimetry and gas absorption measurement. Additionally, the monoliths could maintain the well-defined 3D skeletal structure with a tunable amount of GMA monomer in polymerization system for improved permeability and functionality while the content of other components is fixed. Meanwhile, the successful application of the optimal monolith for separation of both small molecules and lager biomolecules was provided proof of its potential utilization in HPLC. Considering different requirements, the application of the novel well-defined 3D skeletal monolith could be easily widened via post-modification because of its possessing epoxy functionality. Hopefully, the newly synthesized PGMA with different molecular weights could be developed as a novel candidate polymeric phase separator for fabricating various monoliths with well-defined structure, comparable to commercially available ones. (C) 2012 Elsevier Ltd. All rights reserved.