The syntheses and single crystal structures of five new tetracyanidoborate salts with N‐based cations are described. Three of these compounds contain cations with acidic H atoms. The H‐bond strength, expressed by D‐A distances is correlated with a shift of the CN stretching mode frequency in the IR spectra. Melting points are found between 59 °C and 214 °C, i. e. at the borderline between ionic liquids and molten salts. Isothermal annealing indicates slow decomposition. Solubility tests in polar solvents show a strong dependence on the cation.

A series of nine different known ionic liquids or low melting salts was synthesised and purified. They are composed of the [NTf2]– (bis(trifluoromethane)sulfonimide), [OTf]– (trifluoro‐methane‐sulfonate), or [B(CN)4]– (tetracyanidoborate) anion and [Ph4P]+ (tetraphenylphosphonium), [Ph3BzP]+ (triphenylbenzyl phosphonium), [nBu4P]+ (tetra‐nbutylphosphonium), [nBuPh3P]+ (tri‐phenyl‐nbutylphosphonium), [nBu4N]+ (tetra‐nbutylammonium), or the [PPN]+ (bis(triphenylphosphine)iminium) cation. Precise vapour pressure data and enthalpies of vaporisation were measured using the Quartz Crystal Microbalance (QCM) method and evaluated. Structure‐property relations are established using the obtained data as well as literature known data of ILs with alkyl‐substituted imidazolium cations. It turns out that ILs with the tetracyanidoborate anion have even higher values of the enthalpy of vaporisation than those with the common [NTf2]− or [OTf]− anion and therefore are even less volatile.

First lead(II) tetracyanidoborates were synthesized and the crystal structures of [Pb2(H2O)4{B(CN)4}4] (1) and [Pb2(O2CCH3)2{B(CN)4}2(C2H5OH)2] (2) were determined by X‐ray diffraction. Both compounds contain dinuclear centrosymmetric Pb2O2 cores. The Pb(II) ions in both compounds have heteroleptic holodirected coordination environments constituted by three O and five N atoms (O3N5) in 1 different from that in 2, which is constituted by four O and four N atoms (O4N4). In 1 the bridging O atoms of the Pb2O2 unit belong to the water ligands, whereas in 2 one O atom of each of the two acetate ligands has the bridging functionality whereas the second one is terminally bonded, i. e. the acetate ligand coordinates in a μ2‐η2:η1 fashion. In 2, all four N atoms of the tetracyanidoborate anion are coordinated to neighboring Pb2O2 units, whereas in 1 free cyanido groups exist. Nevertheless, in both structures the dinuclear Pb units are three‐dimensionally interconnected, i. e. they are Pb(II) coordination networks. On heating compound 1 loses the aqua ligands and anhydrous Pb[B(CN)4]2 forms.

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