  We investigate the possibility of observable proton decay within the improved
missing doublet model (IMDM75), which utilizes a Higgs in 75 representation for
$SU(5)$ gauge symmetry breaking. The realization of observable proton decay in
IMDM75 is made feasible primarily due to chirality nonflipping color-triplet
mediation, while chirality flipping mediation is adequately suppressed. Our
predictions suggest a range of proton lifetimes between $10^{34}-10^{36}$ yr,
which can be observed in upcoming experiments such as Hyper-K and DUNE, for a
corresponding range of color-triplet mass parameter $M_T$ in the order of
$10^{11}-10^{14}$GeV. IMDM75 is shown to offer unique predictions for branching
ratios when compared to other grand unified theory models. Finally, a
realization of successful gauge coupling unification is achieved, even with the
presence of particles at intermediate scales.
