We investigate the effects of thermodynamical variables, intermolecular interactions and block lengths on phase and orientational ordering of guest tri-block co-polymers in a host glassy matrix of short molecular rods. The A and B blocks can align to the short rod molecules. Using a field theoretic formulation we demonstrate the occurrence of a nematic-nematic (N/N) first order transition from a guest stabilized to a guest-host stabilized region, a reentrant transition from a guest stabilized nematic region to a host only stabilized regime via an isotropic phase and the possibility to selectively stabilize the orientation of the A or/ and B blocks. (c) 2005 Elsevier B.V. All rights reserved.