Phase relations of pseudo binary alloys of (Sr, X)Al2 (X=Ca and Ba) and Sr(Mg, Al)2 have been investigated and the stability of the pseudo binary Zintl alloys were clarified. Hydrogenation properties of these alloys were investigated. Starting from SrAl2 Zintl phase alloy, two novel hydrides such as SrAl2H2 Zintl hydride and Sr 2AlH7 were synthesized. BaAlH5 and Ba 2AlH7 were synthesized from Ba7Al13 intermetallic compound. Crystal structures of these novel hydrides (Sr 2AlH7 and BaAlH5) were refined using powder X-ray and neutron diffraction.