Shiva, well only you can answer this question, because it's all about your interest.

Both MSc pharmaceutical chemistry and MSc Forensic science are good in demand professions to pursue.

One one side, there is very good scope for pharmaceutical chemistry. It is one of the important branches of pharmacy. You can join research and development in different companies. The salary package might range from 3-12 lakhs per year.

On the other side, Forensic science has no end.

If you want to work to mostly for the government to catch hold of the criminal minds, then this field is for you. Though jobs here are not so openly discussed, but you can get information about these from service commission websites. Go for PSC, crack it and then there are high paying and  reputed jobs available for you.

Now it's all depends on your interest. We can still make our career in a less in demand field, if we have passion in it.

I wish you good luck!