Oxidation of the ferrocenyl ketones FcCH 2 COR 1 [Fc = (C 5 H 5 )Fe(C 5 H 4 ); a R = Ph, b R = C 6 H 4 Ph-4] with selenium(IV) oxide provides only modest yields of the corresponding 1,2-diketones FcCOCOR 2, but substantial yields of the 1,4-butanediones RCOCH(Fc)CH(Fc)COR 3 resulting from C-C coupling. Compounds 3 exist in two diastereoisomeric forms, racemic and meso, and crystal structures are reported for rac-3a, rac-3b and meso-3b, as well as for 1b.