Exploring the fundamental building block is essential for constructing functional materials with extended topological configuration. In the polymeric nitrogen system, there are still no fundamental building blocks that have been reported. Here, we successfully synthesize the buckled 1-dimensional (1D) band-shaped and 2-dimensional (2D) layered polymeric nitrogen frameworks with N18 ring as a building block for the first time. In addition, the dimensions of polymeric nitrogen framework can be regulated by the pressure conditions. Bader charge analyses indicate that the charge transfer from the La atom to the low-order bonded nitrogen atom plays a crucial role in stabilizing these two low-dimensional polymeric frameworks. Both LaN16 and LaN8 are promising high-energy-density materials (HEDMs). This study reveals that the N18 ring can serve as a building block, similar to the fundamental six-membered ring in carbon-based materials, for constructing novel polymeric nitrogen materials with extended frameworks.