Racemic 2-isopropyl-3-(2-nitrob-enzyl)-1,3-thiazolidin-4-one crystallizes in the space group P2(1)2(1)2(1) with Z '=2: two different interpenetrating three-dimensional frameworks formed by C-H center dot center dot center dot O hydrogen bond

rac-2-Isopropyl-3-(2-nitrobenzyl)-1,3-thiadiazolin-4-one, C13H16N2O3S, is a rare example of a racemate crystallizing in the space group P2(1)2(1)2(1), with one molecule each of S and R configurations, whose conformations are almost mirror images, within the asymmetric unit. The molecules of S configuration are linked by two C-H center dot center dot center dot O hydrogen bonds into a three-dimensional framework, and the molecules of R configuration are linked by two further C-H center dot center dot center dot O hydrogen bonds into a different type of three-dimensional framework; the two frameworks are linked by a fifth C-H center dot center dot center dot O hydrogen bond.