The mechanical properties of sandwich composites are more depended on the core material structure. Damage of the commercial honeycomb core materials are generally occurred as delamination the unit-cells of core material under mechanical or impact loads. In addition, the common feature of commercial core materials is their high-cost. Economic approach of the current researches are led the studies based on the principle of converting ordinary materials into advanced materials. Nowadays, the development of low-cost/high-performance products that serve to reduce environmental impact is an important requirement. In present study, a novel core material is developed for sandwich composites by using a special stitching design. The developed core structure is defined as ‘rhombus core’ which offers a lower cost/higher performance compared to commercial core materials. The compressive behavior of rhombus and commercial core structures are compared. Rhombus cores showed the highest compressive strength and retained their structural integrity after compressive load without any delamination/crushing at stitching regions.