A blend monolith of polycarbonate and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) with a three-dimensional continuous interconnected porous structure is fabricated through a non-solvent-induced phase separation (NIPS) method. By tuning the solvent composition for NIPS, the monolith of the two immiscible polymers is obtained successfully. The blend monolith, with its large surface area and high thermal stability, may find use in various potential applications of porous materials.