The diverse efforts to rationally construct microporous solids using porphyrins and metalloporphyrins as molecular building blocks are reviewed. Porphyrin-based molecular crystals, hydrogen-bonded networks, and metal ion coordination polymer networks are examined in detail. Recurring geometrical motifs observed in the structural frameworks of different porphyrinic solids are emphasized, and the influences of solvates and guest molecules are explored. Attempts to construct porphyrin-siloxane networks are also reviewed. (C) 2000 Academic Press.