SrCoO2.5 (SCO) is a charge transfer insulator with 3d6 ground state configuration leading to antiferromagnetic nature. It is observed that substrate induced strain engineering modifies the ground state of SCO thin film with 3d7L (L:O-2p hole) configuration causing negative charge transfer energy.The consequent strong hybridization between O-2p and Co-3d bands causes a hole in O-2p band leading to hole mediated unconventional ferromagnetic ordering in SrCoO2.5 thin film. This opens up a new avenue to tune the electronic structure vis a vis magnetic property via strain engineering.