An improved procedure for pattern recognition in 2-dimensional NMR spectra is described. The algorithm uses only the signs of the signals, and begins by searching for responses that are characteristic of 3-spin subsystems, which are then identified as constituent parts of larger N-spin systems. The method relies on the comparison of cross-peak patterns obtained in 2 complementary 2D (2-dimensional) spectra. For the sake of demonstration, a conventional ID spectrum of a mixt. of small mols. is decompd. into subspectra of the constituents. The chem. shifts and coupling consts. resulting from the anal. are presented in a form which makes the presentation of the exptl. 2D spectra superfluous. [on SciFinder (R)]