Cu(I) and Ag(I) iodidometalates have been investigated for both their rich structural chemistry, as well as for useful properties like luminescence. Here, we present the synthesis and crystal structure of (BzA)[MI2] · 0.5 H2O (BzA = benzylammonium; M=Cu (1), Ag (2)). The two compounds are isostructural and show a previously unknown layered anion motif that can be described as a 44 net constructed via corner-sharing of M2I6 subunits, built from two edge-sharing MI4 tetrahedra.