Calculated dissociation energies and molecular bending barriers of pentacene (a linear molecule), C₃₁ H₁₅ (a two-row molecule), C₄₀H₁₆ (a three-row molecule), and circumovalene. The dissociation energy for removing a terminal side hydrogen atom from these molecules is about 4.8 eV. The molecular bending barrier increases from ~5.5 to ~13.9 eV as the number of rows increases. For ovalene, two different bending pathways, depending on the position of H loss (denoted with a yellow circle), are investigated. The barrier increases from ~13.9 eV for the loss of a duo-hydrogen to ~16.3 eV for the loss of a solo-hydrogen.