  We report novel spectropolarimetric observations of sunspots carried out with
the Tenerife Infrared Polarimeter (TIP) in a near-IR spectral region around
15410 A, which is known to contain two groups of prominent OH lines that show
circular polarization signals of opposite polarity. Surrounding these
well-known OH lines, we have discovered the presence of CN lines of the $\Delta
v=1$ band which show anomalous polarization profiles. Although the Stokes V
signals of the OH lines are antisymmetric and with a sizable amplitude, the CN
lines show almost negligible circular polarization. On the contrary, the linear
polarization signals turn out to be much stronger in the CN lines than in the
OH lines. Interestingly, these CN lines present striking antisymmetric linear
polarization profiles, which we are able to explain and model via the
Paschen-Back effect theory for diatomic molecules. The presence of such
peculiar CN lines in the same spectral region of the OH lines may be useful to
improve our empirical knowledge of solar magnetic fields via the simultaneous
observation and modeling of the transverse and longitudinal Zeeman effects in
two different molecular species.
