In this work, we characterize – for the first time – in the gas phase infrared spectra of three isomeric Polycyclic Aromatic Hydrocarbon (PAH) cations of C24H14 composition that belong to distinctly different symmetry groups (C2h, Cs and C1). Mid-infrared (Mid-IR) spectra are recorded by means of infrared multiple photon dissociation (IRMPD) spectroscopy at the free electron laser for infrared experiments (FELIX) laboratory. The measured infrared (IR) band positions compare reasonably well with density functional theory (DFT) calculated values. The number of IR active bands increases as the symmetry of the molecule lowers. The IRMPD spectra of irregular PAHs are found to be dense and do not resemble the sharp signatures typical of astronomical IR bands, but rather look like the broad plateau on which these are perched. This lends credit to the GrandPAH hypothesis that suggests that small and irregular PAHs are weeded out by the strong interstellar radiation field and only large regular PAHs remain.