The fluorinated and non-fluorinated dibenzylidene-4-piperidones were synthesized and their structures examined using X-ray crystallography. Interestingly, the para-fluorosubstituted dibenzylidene compound, in contrast to other analogs, is characterized by C-H. . . F bonded one-dimensional packing motif. To evaluate the ability of hydrogen bond donors and acceptors for forming interactions, in general and competitive situation, we have defined statistical descriptors. Analysis of Cambridge Structural Database using these newly defined parameters reveals high propensity of C-H. . . F interactions in organic crystals. The present structural study suggests much larger role of fluorine driven intermolecular interactions that are even though weak, but possess significant ability to direct and alter the packing.

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