The X-ray crystallographic analysis of 8-fluoro-1-(p-anisylselanyl)naphthalene (1) revealed that the F and Se atoms and the ipso-carbon of the p-anisyl group (C(An)) aligned linearly. The F atom and the Se-C(An) bond lay on the naphthyl plane : the nonbonded distance between F and Se atoms was 2.753(3) Angstrom and the FSeC(An) angle was 175.0(1)degrees. Ab initio MO calculations with the 6-311++G(3df, 2pd) basis sets performed on the model compound of 1, HF ... SeH2, where the aryl groups of 1 were replaced by hydrogens. The calculations exhibited that the energy minimum was achieved when the F, Se, and C(An) atoms aligned linearly. Charge transfer in the formation of HF ... SeH2 was suggested to occur from F to SeH2 on the basis of natural population analysis, which supported the np(x)(F)-sigma*(Se-C(An)) interaction.