Make new macbook work on iMac Is there anyway I can make my new Macbook (12 inch) that comes with only USB-C work its display on my iMac? I used to do it with the my previous macbook air, but the new one does not have a thunderbolt port. 

I also have the USB-C - HDMI adapter but apparently it is of no use in this scenario.
Thunderbolt Gen 1 and 2 don’t support USB 3.1, Type C or even 3.0 for
  that matter. An adapter wouldn’t have fixed this problem. However,
  Apple is releasing Thunderbolt 3 later in 2015. It’s not ready yet,
  because it’s developed with Intel and now Gen 3’s functionality is
  tied to Skylake chips – which will replace Broadwell shortly. I know.
  You’re thinking “But Broadwell just came out!” That’s true, but only
  because of delays. Now, you may wonder how a new MacBook without a
  Thunderbolt port or a Skylake chip will support a Thunderbolt Display.
  
  Well, in short it won’t. That is unless Apple releases a firmware
  update for their Thunderbolt cables. Which they won’t. So it probably
  won’t support it. Considering the last time they updated it, I think
  we’ll see an update at WWDC, with a USB C port on the display itself.


http://9to5mac.com/2015/03/09/apples-12-macbook-gets-new-usb-c-power-vga-usb-and-hdmi-adapters/


  What might be a solution is an ungodly combination of:
  
  
  StarTech’s female Mini DisplayPort to male DisplayPort adapter ($4.50)
  A female-to-female DisplayPort coupler ($13.50)
  a DisplayPort-to-HDMI cable (as little as $6)
  Apple’s $79 USB-C Digital AV Multiport Adapter, which has an HDMI port
  on it in addition to pass-through USB-C power and USB Type A 3.1 for
  data
  


http://www.macworld.com/article/2966043/displays/how-to-connect-an-apple-display-to-a-usb-c-macbook.html

Good luck ^^