Two series of asymmetric ferrocene diphosphines, namely the dppf-type ligands R2PfcPPh2 (protected as BH3 adducts; fc = ferrocene-1,1′-diyl) and their semi-homologous counterparts R2PfcCH2PPh2 (both in free and BH3-protected form), with diverse PR2 groups (R = cyclohexyl, isopropyl and tert-butyl), were prepared and further converted into the respective phosphine selenides, R2P(Se)fcP(Se)Ph2 and R2P(Se)fcCH2P(Se)Ph2, which were in turn used to evaluate the electronic properties of these diphosphines through 1JSeP coupling constants. When reacted with [PdCl2(MeCN)2] or [PdCl2(cod)] (cod = cycloocta-1,5-diene), the dppf-type ligands exclusively afforded the chelate complexes [PdCl2(R2PfcPPh2-κ2P,P′)], whereas the more flexible, homologous ligands produced mixtures mainly containing the similar chelate complexes [PdCl2(R2PfcCH2PPh2-κ2P,P′)] and the P,P′-bridged dimers [PdCl2(μ(P,P′)-R2PfcCH2PPh2)]2.