We are in the process of transferring our legacy system to asp.net. We have multiple solutions all containing one project each. We have a lot of situations whereby a class in "Solution A" will call a class in "Solution B" and vice versa. Does this constitute a circular reference or does this term only refer to projects which call other projects within the same solution??? We know that visual studio will now build projects which call other projects inside the same solution due to circular references, however we have not run into this error with the multiple solution/one project setup...We are wondering if this setup will cause us any problems down the road? or Should we combine solutions to eliminate these types of calls and be forced to have longer build times???