NOVELTY - Three-dimensional porous polymeric structure comprises a porous polymer structure optionally with particles within the pores of the polymer, where the pores have a narrow pore-size distribution.    USE - The porous structure is useful in a process selected from solid phase synthesis of a species selected from peptides, oligonucleotides, oligosaccharides; solid phase extraction; solid phase organic chemistry; immobilization of a species selected from solid phase reagents, metal and other catalysts, bio-catalysts, enzymes, proteins, antibodies including polyclonal and monoclonal antibodies, whole cells and polymers; cell culturing; preparation of a stationary phase for chromatographic separation; or for use as an absorbent; or for use as an insulating material or in tissue regeneration. It can also be used in a process for continuous production of monoclonal antibodies or other bioactive molecules secreted or excreted by a cell or cell-free systems in which the cell or non-cell system is grown on or otherwise attached reversibly or irreversibly to the three-dimensional structure. It can further be used as a production unit for an organic body, where organic body is selected from stem cells, organs and bone (all claimed). The porous structures can further be used in porous monoliths as stationary phases for chromatography; in porous discs for filtration of species; in porous materials for electroosmotic pumps; in solid supports for solid phase synthesis and other chemical transformations; in insulating materials; in porous membranes for use in fuel cell applications; in and multi-dimensional scaffolds for tissue engineering.    ADVANTAGE - The invention provides means of producing novel three-dimensional structures with a narrow pore size distribution in a relatively inexpensive manner, where the structures may be adapted for use in a wide range of applications with chemical and physical characteristics that have not been previously achievable.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is a process for producing three-dimensional porous structure comprising closely packing particles in a zone to provide a 3 dimensional array of the particles, contacting a polymerizable monomer or a solution of a monomer with the array such that the monomer or the solution fills interstitial spaces between the particles and effecting polymerization of the monomer where a polymer structure is formed around the particles and optionally removing the particles from the structure.