Polycyclic aromatic hydrocarbons (PAHs) have been heralded as mutagenic and carcinogenic substances and currently, their emissions are subject to regulatory control due to recently imposed stricter environmental regulations. Hence, it has become necessary to have a detailed understanding of their chemistry. In this work, a short review of the available PAH relevant counterflow diffusion flame datasets is presented. Following that, the reliability of four widely used PAH mechanisms and the revised PAH mechanism, within the scope of this work, is assessed by validating them against these collected experimental datasets. The formation of the first aromatic ring is investigated based on the performed reaction path analyses. The results show that the dominant reaction pathways for the formation of benzene are “even carbon atom” pathways (H-abstraction acetylene addition) and “odd carbon atom” pathways (recombination of propargyl radicals). The dominance of one pathway over the other was found to be strongly dependent on the fuel structure and its doping with other components.