- Synthesis and structure of the seleno derivative of maltol (selenomaltol) is described. Structural and energetical properties of possible selenomaltol structures have been calculated at the B1LYP/6-311++G(d,p) level. The lowest energies are always predicted for the keto-enol tautomer. To verify obtained results several standard experimental methods, namely: elemental analysis, mass spectrometry, infrared and NMR spectroscopies and X-ray crystallography have been used. Investigation of IR and NMR spectra clearly indicate that the oxygen atom of exocyclic keto group on maltol was replaced by selenium. Experimental crystallographic results support this conclusion.