The first systematic study on the use of tricyanoborates as ligands is presented. The tricyanoborates [RB(CN)(3)](-)(R = oct and Ph) can be prepared by direct cyanation of RBCl2 precursors as well as by thermolysis of the corresponding isocyanides [RB(NC)(3)](-). The first organo-cyanogallates [RGa(CN)(3)](-) (R = Bu, C6H2-2,4,6-Me-3) were prepared from the corresponding dichloride, the structure of Et4N[mesGa(CN)(3)] being confirmed crystallographically. The reaction of equimolar [RB(CN)(3)](-) (R = oct, Ph) and [Cu(MeCN)(4)](+) afforded two-dimensional polymers [RB(CN)(3)CU(NCMe)]. The sheets arise via conjoined hexagonal B3CU3(CN)6 rings with chair conformations. The reaction of excess [PhB(CN)(3)](-) and [Cu(MeCN)(4)](+) gives the polymer [K(18-crown-6)]{Cu[PhB(CN)(3)](2)}. Treatment of [PhB(CN)(3)](-) with [CU(PCy3)(2)(NCMe)(x)]PF6 gave the one-dimensional polymer [PhB(CN)(3)CU(PCy3)(2)], wherein two of the three BCN substituents are coordinated.