Gas-grain astrochemical model results for the calculated abundances (relative to H₂) of the most important species involved in the formation of aromatic molecules in dark clouds, shown as a function of cloud age. The horizontal gray region represent the observed abundances in TMC-1, with an arbitrary uncertainty of plus or minus a factor of 2: CH (Suutarinen et al. 2011), C₂H (Sakai et al. 2010; Turner et al. 2000), c-C₃H₂ (Park et al. 2006; Turner et al. 2000), l-C₃H₃⁺ (Silva et al. 2023), CH₃CCH (Askne et al. 1983; Irvine et al. 1981; Markwick et al. 2002; Turner et al. 1999), C₃H₆ (Marcelino et al. 2007), and c-C₅H₆ (Cernicharo et al. 2021a). The vertical gray region indicates the chemical age obtained by minimizing the distance of disagreement (Wakelam et al. 2006), which in this study involves the differences between the observed and modeled abundances of 62 species in TMC-1.