Sending manuscript to a journal that rejected an earlier paper As a beginner researcher, several years ago, I sent some (2-3) papers to a quality journal (with ISI IF). The papers were rejected.
Now I am preparing a manuscript, which is in my opinion much more mature.
In the meantime I had some papers published in other journals.
Now I am considering the same journal again, because of the topic.
Is it a good idea ? Or is there going to be some bias because of earlier rejections ?
Just to clarify: this is a completely new manuscript.
This is perfectly legit. You are not forbidden to submit ever again to a journal that has rejected one of your earlier manuscripts. Indeed, rejections happen for everyone. It is best not to take them too badly.

Now, it would be a different story if you resubmitted the same paper that was previously rejected, or a version with only minor updates. Sending an entirely new manuscript, or a much more mature version, is unproblematic.


  Or is there going to be some bias because of earlier rejections ?


Important journals get many submissions, the majority of which they have to reject. I think it is very unlikely that the responsible editor even remembers that you already had a paper rejected a few years back. And even if (s)he does, it is unlikely that (s)he holds it against you. As I said, rejection is something that happens to every researcher, at least now and then.