  We report on a detailed study of the stellar populations and ionized gas
properties in the merger LIRG NGC 2623, analysing optical Integral Field
Spectroscopy from the CALIFA survey and PMAS LArr, multiwavelength HST imaging,
and OSIRIS narrow band H$\alpha$ and [NII]$\lambda$6584 imaging. The spectra
were processed with the STARLIGHT full spectral fitting code, and the results
compared with those for two early-stage merger LIRGs (IC 1623 W and NGC 6090),
together with CALIFA Sbc/Sc galaxies. We find that NGC 2623 went through two
periods of increased star formation (SF), a first and widespread episode,
traced by intermediate-age stellar populations ISP (140 Myr-1.4 Gyr), and a
second one, traced by young stellar populations YSP ($<$140 Myr), which is
concentrated in the central regions ($<$1.4 kpc). Our results are in agreement
with the epochs of the first peri-center passage ($\sim$200 Myr ago) and
coalescence ($<$100 Myr ago) predicted by dynamical models, and with high
resolution merger simulations in the literature, consistent with NGC 2623
representing an evolved version of the early-stage mergers. Most ionized gas is
concentrated within $<$2.8 kpc, where LINER-like ionization and high velocity
dispersion ($\sim$220 km/s) are found, consistent with the previously reported
outflow. As revealed by the highest resolution OSIRIS and HST data, a
collection of HII regions is also present in the plane of the galaxy, which
explains the mixture of ionization mechanisms in this system. It is unlikely
that the outflow in NGC 2623 will escape from the galaxy, given the low SFR
intensity ($\sim$0.5 M$_{\odot}$yr$^{-1}$kpc$^{-2}$), the fact that the outflow
rate is 3 times lower than the current SFR, and the escape velocity in the
central areas higher than the outflow velocity.
