We present here the most recent results obtained in the laboratory from various kinds of carbon‐based submicron grains. The joint use of VUV, IR and Raman spectroscopy allows to characterize them and to determine their structural and spectral properties. We compare our results with similiar data obtained by various authors on other kinds of carbonacous materials produced by UV irradiation as well as by ion bombardment. We are driven to conclude that carbon‐based solid particles tend to evolve towards a common final structure, as a consequence of various kinds of processing. The merging of all these experimental evidences may bring to some interesting astrophysical implications about the actual composition of cosmic dust.