  We report on detailed structural, electronic and magnetic studies of
GdMn$_{1-x}$Cr$_x$O$_3$ for Cr doping levels 0 $\le$ $x$ $\le$ 1. In the solid
solutions, the Jahn-Teller distortion associated with Mn$^{3+}$ ions gives rise
to major changes in the ${bc}$-plane sub-lattice and also the effective orbital
ordering in the ${ab}$-plane, which persist up to the compositions $x$ $\sim$
0.35. These distinct features in the lattice and orbital degrees of freedom are
also correlated with $bc$-plane anisotropy of the local Gd environment. A
gradual evolution of electronic states with doping is also clearly seen in O
$K$-edge x-ray absorption spectra. Evidence of magnetization reversal in
field-cooled-cooling mode for $x$ $\ge$ 0.35 coinciding the Jahn-Teller
crossover, suggests a close correlation between magnetic interaction and
structural distortion. These observations indicate a strong entanglement
between lattice, spin, electronic and orbital degrees of freedom. The
nonmonotonic variation of remnant magnetization can be explained by doping
induced modification of magnetic interactions. Density functional theory
calculations are consistent with a layer-by-layer type doping with
ferromagnetic (antiferomagnetic) coupling between Mn (Cr) ions for intermediate
compound ($x$ = 0.5), which is distinct from that observed for the end members
GMnO$_3$ and GdCrO$_3$.
