In the present work, biologically important molecules benzoxazole and its derivatives 2-phenyl benzoxazole and 4-amino-2-phenyl benzoxazole were investigated theoretically using molecular orbital and density functional theory. Semi empirical MO calculations, AM I procedure, have been carried out on these molecules. These include charge density, heat of formation, ionization potential, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies and energy gaps. Solvation analysis on these compounds have been carried out by the polarizable continuum model (PCM) at the B3LYP with 6-31G* level of theory. The effects of electrostatic and non-electrostatic interaction contribution to free energy of solvation were discussed.