This article details new ignition delay time experiments carried out on blends of n-pentane and either NO or NO<sub>2</sub> in the rapid compression machine facility at RWTH Aachen University. Further, a new chemical kinetic mechanism is developed which is able to well-reproduce the experiments and significantly improve over recently published mechanisms. <br>This work has particular value for publication as it adopts a systematic, class-based approach to mechanism development for interactions with nitrogenated species. <br>