  We present new modelling of the spectrophotometric properties of intermediate
age stellar populations in the near-infrared (NIR). We take into account the
evolutionary and spectroscopic properties of the Asymptotic Giant Branch (AGB)
stars which dominate the integrated NIR emission of those populations. The
predictions of spectrophotometric narrow-band molecular indices require the use
of an effective temperature -- colour (or spectrum) calibration for AGB stars;
synthetic indices show a strong dependence upon this calibration. Preliminary
results of NIR observations of a supermassive 500 Myr old stellar cluster in
the prototypical merger remnant NGC 7252 are presented. The spectra are indeed
consistent with intermediate age models dominated by light from AGB stars, a
significant fraction of which may be carbon rich. Implications for the stellar
inputs used in the modelling of intermediate age stellar populations and their
NIR emission are discussed.
