Can I use a Mini DisplayPort to Display port for connecting a 2011 iMac to an external display?

[RealSkyDiver]

I’m dualbooting Win7 on it and want to connect it to an external monitor. Would any such cable work?

 

[splifingate]

I don't see why not . . . I have a mDP->HDMI attached to an old Dell that works just fine

 

[paardenkapper]

Yes you should be able to do that.
But you should not use Windows 7 anymore - it's deprecated and insecure.

Also the iMac can also be used as an external display when you're using High Sierra on it (target display mode) but you surely know that.