Cellular materials are of great interest in aerospace applications for enabling lightweight structural components. Previous investigations of 3D cellular void-array materials has demonstrated that compressive failure occurs on characteristic planes and directions for any given void arrangement. this investigation seeks to clarify the role of such failure on the properties of these materials and to investigate the possibility of using hierarchical features to give enhanced properties. 2D cellular void array materials comprising periodic arrays of circular voids were fabricated from flat sheet by laser cutting. Compression tests were conducted over a range of void arrangements and porosity levels. In particular the loci of failure and property-porosity relationships were investigated. Once the regular void-array structures had been characterised, hierarchical features were introduced into selected structures and the effects on mechanical properties was assessed. The eventual goal of this research is to extrapolate learnings from the simplified 2D structures to 3D cellular structures thereby increasing mechanical performance with the minimum weight penalty.