The reaction of organoselenicles and -diselenicles (R2Se and (RSe)(2)) with XeF2 furnished the corresponding organoselenium(IV) difluoride.s R2SeF2 (R = Me (1), Et (2), iPr (3), Ph (4), Mes (=2,4,6-(Me)(3)C6H2) (5), Tipp (=2,4,6+Pr)(3)C6H2 (6), 2-Me2NCH2C6H4 (7)), and trifluorides RSeF3 (R = Me (8), iPr (9), Ph (10), Mes (11), Tipp (12), Mes* (=2,4,6-(tBu)(3)C6H2) (13), 2-Me2NCH2C6H4 (14)), respectively. In addition to characterization by multinuclear NMR spectroscopy, the first molecular structure of an organoselenium(IV) difluoride as well as the molecular structures of subsequent decomposition products have been determined. The substitution of fluorine atoms with Me3SiN3 leads to the corresponding organoselenium(IV) diazides R2Se(N-3)(2) (R = Me (15), Et (16), Pr (17), Ph (18), Mes (19), 2-Me2NCH2C6H4 (20)) and triazides RSe(N-3)(3) (R = Me (21), iPr (22), Ph (23), Mes (24), Tipp (25), Mes* (26), 2-Me2NCH2C6H4 (27)), respectively. The organoselenium azides are extremely temperature-sensitive materials and can only be handled at low temperatures.