Two-dimensional structures are an emerging class of materials within nitride chemistry. We report here our systematic studies of two groups of these layered compounds: 1 Lithium transition metal compounds, Li 3−x−y □ y M x N (M=Co, Ni, Cu, □=Li vacancy) and 2 ternary transition metal nitrides of general formulation AMN 2 (A=alkaline earth metal, M=Ti, Zr, Hf). Compounds in class 1 are based on the hexagonal Li 3 N structure, unique to nitrides. Compounds in group 2, by contrast, crystallise with oxide structures (α-NaFeO 2 or KCoO 2 ). Specific and unusual synthetic methods have been developed to reproducibly prepare these compounds. Compounds in series 1 contain ordered or disordered Li vacancies at increased levels relative to the parent Li 3 N, itself a Li + fast ion conductor. Nitrides in series 2 should be nominally diamagnetic (S=0), yet magnetic measurements reveal behaviour seemingly inconsistent with this assumption.