(±)-N-Isonicotinoyl-2-amino-5-chlorobenzhydrol (1) is a rice plant growth regulator which shortens the second leaf sheaths. One of the enantiomers, (S)-1, was obtained by microbiological asymmetric reduction of 2-amino-5-chlorobenzophenone using Rhodosporidium toruloides followed by isonicotinoylation. Several substituted benzhydrol derivatives were also prepared by use of the same biological method and converted to N-isonicotinoyl compounds. The growth-regulating activities of these compounds were evaluated.