According to the present knowledge, a composition of interstellar <br />
absorbing matter is very complex: e.g., the already <br />
detected molecules consist of up to 13 atoms and some larger <br />
species have already been suggested. Another, perhaps most <br />
prominent, evidence of intricate processes of molecular synthesis <br />
and destruction taking place in interstellar medium is the <br />
existence of diffuse interstellar bands (DIBs) - the longest <br />
standing unsolved problem in all of spectroscopy. DIBs were <br />
discovered as long ago as in 1921 (Heger) but their carriers <br />
remain unknown despite considerable efforts of astronomers and <br />
despite a progress in observational astronomy during last 10-15 <br />
years. The list of these spectral lines or bands continues to <br />
grow, including more and more weak DIBs and reached now ~300 features. <br />
I will tell about the current state of the problem of DIBs <br />
identification.