The screening of resin-bound combinatorial libraries with pairs of dye-tagged substrates is a powerful strategy for discovering selective receptors. However, implementation has been hampered by a lack of complementary but chemically similar dyes. We now show that the well-established Disperse Red 1 and the recently-introduced Bristol Blue 1 can be used in parallel to synthesise 'pseudoenantiomeric' analogues of N-acetyl-alpha-amino acids and of the anti-inflammatory drug Naproxen. A steroid-based receptor library has been prepared and screened with these substrates. Preliminary results suggest that some members may be highly enantioselective receptors for N-acetyl-alpha-amino acids. (C) 2009 Elsevier Ltd. All rights reserved.