1,3-Diaminobenzene reacts readily with PPh2Cl to give N,N,N',N'-tetrakis(diphenylphosphanyl)-1,3-diaminobenzene (1) in excellent yield. The dinuclear complex [1,3-{cis-Mo(CO)(4)(PPh2)(2)N}(2)C6H4] (2) is obtained in high yield from I and cis-[Mo(CO)(4)(NCEt)(2)]. Compounds 1 and 2 were characterized by NMR spectroscopy (H-1, C-13, P-31) and by crystal structure determination. The latter shows the formation of a bis-chelate complex with Mo-P-N-P four-membered rings.