Creating hierarchical porosity in MOFs has attracted significant interest due to their immense potential in a wide range of applications from materials to life science. Herein, we report a unique methodology of combining perturbation assisted nanofusion (PNF) with microwave (MW) stimuli to generate wide additional pores from (5-18) nm in the prototype MOF, NiMOF-74. An optimized combination of microwave exposure, perturbation in form of stirring, and solvent effect induces additional mesoscale porosity by fusion of MOF nanoparticles. The effect of microwave is realized by varying reaction time and medium using a range of solvents having different dielectric constant (DMSO, DMF, DMA, acetone, EA, and THF). Introducing this method, for the first time, we are able to generate a wide scale mesopore by fusion of nanoscale microporous MOF within a short reaction time by vigorous stirring, without using any template. This additional mesopore, thus generated, has been exploited by encapsulating 4.6 mu mol.g(-1) of large biomolecule Vitamin B-12 (VB12).