To mimic the architecture of a natural extracellular matrix component-collagen, nona-fibrous matrices have been created with synthetic biodegradable polymers in our laboratory using a phase-separation technique. To improve the cell seeding, distribution, mass transport, and new tissue organization, three-dimensional macroporous architectures are built in the nano-fibrous matrices. Water-soluble porogen materials are first fabricated into three-dimensional negative replicas of the desired macroporous architectures. Polymer solutions are then cast over the porogen assemblies in a mold, and are thermally phase-separated to form nanofibrous matrices. The porogen materials are leached out with water to finally form the synthetic nano-fibrous extracellular matrices with predesigned macroporous architectures. In this way, synthetic polymer matrices are created with architectural features at several levels, including the anatomical shape of the matrix, macroporous elements (100 mm to millimeters), interfiber distance (microns), and the diameter of the fibers (50-500 nm). These scaffolding materials circumvent the concerns of pathogen transmission and mmunorejection associated with natural collagen. With the flexibility in the design of chemical structure, molecular weight, architecture, degradation rate, and mechanical properties, these novel synthetic matrices may serve as superior scaffolding for tissue engineering.