Key indicators Single-crystal X-ray study T = 298 K Mean (C-C) = 0.004 Å R factor = 0.050 wR factor = 0.095 Data-to-parameter ratio = 8.8 For details of how these key indicators were automatically derived from the article, see Experimental Piperidine (0.38 g, 4.4 mmol) was added dropwise to a solution of a 4methoxybenzaldehyde (0.50 g, 3.67 mmol) and malononitrile (0.50 g, Figure 1 The molecular structure of (I), showing the atom-labeling scheme. Displacement ellipsoids are drawn at the 50% probability level.