In one of our project we have 2 binaries, one for iPhone and other for mac. These two application communicate each other to achieve the functionality. We want the user to download and install the iOS app first and then let him download the Mac application.
Is there a way to restrict the user, if the user try to download the mac app before downloading the iPhone app?
Short answer: If you're referring to the Mac App Store, then no.
Long answer: Both, the App Store and the Mac App Store give you no way to control who downloads your app and you are not able to get information about what a user already downloaded.
You could of course ask for an e-mail address in your iOS app and make sure your users register to a server before you e-mail them a link to a private download page (not the Mac App Store).
General advice: I think there is something wrong with the design of your app. It's not clear to me what you're trying to achieve and I bet your users won't either. If you want to make sure they pay for the iOS app before using the Mac app then just alert them in case they downloaded the Mac app first. You need to write some custom service to check for this of course. If there is some functional problem that requires the iOS app to be launched first then you should solve this yourself and not put that burden on the shoulders of your users.