Hi Arup,
I would recommend figuring out what business transactions on the shop floor need to be supported. Yes, as Christian indicated, MII can be used to provide MES solutions. The drawback is the solution needs to be built. Depending on complexity of your needs, you may be better off checking out SAP ME or SAP CAMS or some other ME solution. I have worked on a number of MES implementations with MII, but there was a lot of effort involved with the more complex projects. ME, etc., are pre-configured for most of the usual MES transactions so implementation requires less custom development and is more of a configuration exercise. ME also uses MII for much of its interfaces. If you go to the parent community (SAP Manufacturing) of SAP MII in SCN, there is more information there on SAP ME which may help you choose a solution.
Regards, Mike
SAP Customer Experience Group - CEG