  In low energy phenomenology to avoid the strong constraints of proton decay
it is usually assumed that light ($\approx $ 250 Gev) leptoquarks couple only
to quark-lepton pairs and light diquarks couple only to quark pairs. In this
paper we present two specific examples where the higgs induced mixing between
leptoquarks and diquarks through trilinear interaction terms reintroduces the
troublesome couplings and gives rise to proton decay. The bound on the unknown
parameters of this scenario that arise from proton life time has been derived.
