Gold nanocrystals stabilized by a chemisorbed mixture of a long-chain alkane thiol, namely dodecanethiol (95 %), and a long-chain dodecanethiol incorporating a receptor, namely 12-mercaptododecyl-1-uracil (5%), have been prepared. In solution, these nanocrystals recognize and selectively bind a long-chain alkane incorporating a complementary substrate, namely, N,N＇-2,6-pyridinediylbis[undecamide].