I'm working for small company, which operates in the automation industry.
The boss hired me because he wants to sell/give some desktop applications to his
current costumers.
He imposes me to use the Netbeans Platform (a generic desktop application framework).
A software engineer friend of his advised him to choose this framework. 
At the moment I created 3 desktop applications with Netbeans Platform.
I like Netbeans Platfom. I really take advantage of modularity, Window System and Lookup.
Unfortunately I'm frustrated to known that I can do the same works with Python and PyQt in a fraction of time.
I've already illustrated to my boss the main advantages of Python, but he doesn't like the
idea to use a language that he never heared of it.
I'm the only programmer who codes desktop applications. And except the framework imposition, I'm free to use whatever I want.
I'm looking for good motivations to convince him to leave Netbeans Platform for Python/PyQt.
P.S: My english is bad, sorry.
First, results speak for themselves: if you can piece together another version of one of your applications in pyqt, and tell him how long it took, it might be motivation enough.
Or, next time you're starting a project, you could prototype four or five different versions of the interface in pyqt in the morning, ask his feedback after lunch, and then say, "if I keep going on these, it'll be done in two days; if I redo this in netbeans, it'll be done in four."
And as for the "never heard of it", feel free to point out that Google uses python extensively, and even hired many of the python developers.
How to convince boss to substitute Java/Netbeans Platform for Python/PyQt?