  The optical UBVRI photometric analysis has been established using SLOAN
DIGITAL SKY SURVEY (SDSS database) in order to estimate the astrophysical
parameters of poorly studied open star cluster IC 2156. The results of the
present study are compared with a previous one of ours, which relied on the
2MASS JHK infrared photometry. The stellar density distributions and
color-magnitude diagrams of the cluster are used to determine the geometrical
structure; limited radius, core and tidal radii, the distances from the Sun,
from the Galactic plane and from the Galactic center. Also, the main
photometric parameters; age, distance modulus, color excesses, membership,
total mass, luminosity, mass functions and relaxation time; have been
estimated.
