When solid MCN (M = Cu or Ag) is ablated with single pulses of a focused Nd-YAG laser (1064 nm, 470-1600 MW cm(-2)), the ions detected by Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS) are [M(n)(CN)(n+1)](-) (M = Cu, n = 1-5; M = Ag, n = 1-4), [M(n)(CN)(n-1)](+) (M = Cu, a = 1-6; M = Ag, n = 1-4), and, for M = Ag, Ag-2(+), Ag-3(+) and [Ag-4(CN)](+). Several mixed-metal species [CumAgn-m(CN)(n+1)](-) and [CumAgn-m(CN)(n-1)](+) are produced on ablation of a CuCN:AgCN mixture. Both [M(n)(CN)(n+1)](-) and [M(n)(CN)(n-1)](+) lose units of MCN on collision-induced dissociation in Ar(g). Reactions of both [M(n)(CN)(n+1)](-) and [M(n)(CN)(n-1)](+) with gaseous NH3, H2S and CO have been followed using FTICRMS. With the anions no addition was detected but dissociation occurred, again by loss of MCN. Dissociation occurred with the cations also, but was frequently accompanied by addition, with bis-adducts predominant. The ranges of addition products detected are : [M(n)(CN)(n-1)(NH3)(x)](+) (M = Cu, n = 2, x = 1-3, n = 3; x = 1-3, n = 4, n = 1-2; M = Ag, n = 2, x = 1-2, n = 3, x = 1-3, and n = 4, x = 1-3); [M(n)(CN)(n-1)(SH2)x](+) (M = Cu or Ag, n = 1-4, x = 1-2); [M(n)(CN)(n-1)(CO)(x)](+) (M = Cu, n = 3-5, x = 1-2; M = Ag, n = 4, x = 1-2). At long reaction times complexes containing HCN are formed in small amount when [Cu-n(CN)(n-1)](+) reacts with H2S. Geometry optimizations using density functional theory (DMol) show that the most stable structures for both aa[M(n)(CN)(n+1)](-) and [M(n)(CN)(n-1)](+) are linear alternations of M and CN, in spear topology.