  The strongest spectroscopic dust extinction feature in the Milky Way, the
broad absorption bump at 2175 \AA, is generally believed to be caused by
aromatic carbonaceous materials -- very likely a mixture of Polycyclic Aromatic
Hydrocarbon (PAH) molecules, the most abundant and widespread organic molecules
in the Milky Way galaxy. In this paper we report identifications of this
absorption feature in three galaxies at $1.4 \lesssim z \lesssim 1.5$ which
produce intervening MgII absorption toward quasars discovered by the Sloan
Digital Sky Survey (SDSS). The observed spectra can be fit using Galactic-type
extinction laws, characterized by parameters [R_V, E(B-V)] ~ [0.7, 0.14], [1.9,
0.13], and [5.5, 0.23], respectively, where R_V=A_V/E(B-V) is the
total-to-selective extinction ratio, E(B-V) = A_B-A_V is the color-excess.
These discoveries imply that the dust in these distant quasar absorption
systems is similar in composition to that of Milky Way, but with a range of
different grain size distributions. The presence of complex aromatic
hydrocarbon molecules in such distant galaxies is important for both
astrophysical and astrobiological investigations.
