A　newly　synthesized　coordination　polymer,　[Cd(DMSO)(H2O)](3)[Fe(CN)(6)](2)　(CdHCF-T),　based　on　Cd2+　and　Fe(CN)(6)(3-)　ions　was　prepared　in　a　DMSO/H2O　mixed　solution　and　crystalized　in　the　trigonal　space　group　P-31c.　This　novel　3D　structure　presented　an　interesting　single-crystal　to　single-crystal　transformation　when　the　coordinated　DMSO　molecules　were　replaced　by　H2O,　forming　a　well-known　Cd　Prussian　Blue　analogue　(Cd-PBA).　This　occurrence　is　a　rare　phenomenon　in　transition　metal　hexacyanometallates　and　may　provide　a　new　strategy　for　obtaining　new　structures　and　overcoming　the　difficulty　of　growing　single　crystals　of　Prussian　Blue　analogues.　Subsequent　gas　sorption　and　separation　investigations　based　on　the　obtained　Cd-PBA　were　also　carried　out　to　evaluate　its　C2H2/CO2　separation　capability.