The 1:1 reactions of [((Pr2N)-Pr-i)BP(H)B((NPr2)-Pr-i)PLi . DME] (1) and [(tmp)BP(H)B(tmp)PLi . DME] (2; tmp = 2,2,6,6-tetramethylpiperidino) with organylhalostannanes have been examined, and stannyl-substituted diphosphadiboretanes, (R(2)N)BP(H)B(NR(2))PSn(Cl)R’(2) (R(2)N = (Pr2N)-Pr-i, tmp; R’ = Me, (t)Bu) have been isolated and characterized. Dehydrohalogenation of these compounds with (t)BuLi produced bicyclic cage compounds P-2(R(2)NB)(2)SnR’(2) (R(2)N = (Pr2N)-Pr-i (9), tmp (8); R’ = (t)Bu) or an oligomer [-P(R(2)NB)(2)PSn(R’(2))-](R(2)N = tmp; R’ = Me). The 2:1 reactions of R’2SnCl2 with 1 and 2 have been studied, and with a small R’ group (Me) a disubstitution product, [HP(tmpB)(2)P](2)SnMe(2) (11), is obtained. With a larger R’ group ((t)Bu), cage products P-2(tmpB)(2)Sn(t)Bu(2) and P-2((Pr2NB)-Pr-i)(2)Sn(t)Bu(2) are isolated. The molecular structures of 8 and 9 have been determined by single crystal X-ray diffraction techniques, and these structures and their spectroscopic features are discussed in relation to other boron-phosphorus cage compounds.