The SU(4) invariant coupling constants which involve singlet are related to those which do not, by assuming SU(4) symmetry in the 'coupling constants forbidden by the OZI rule. The above relations are derived for both meson-meson-meson and baryon-baryon-meson interactions and are applied to tensor meson couplings to two psudoscalars (TPP) and to a pseudoscalar and a vector (TVP). The predicted widths are in reasonable agreement with present data.