An assignment problem (AP) is a meticulous case ofa transportation problem, in which the goal is to allocate a number of facilities to an equal number of activities at an overall maximum profit (or minimum cost, distance, time). It occupies a verysignificantrole in the real physical world. The well-known method applied to solve the APs is the Hungarian method, which generates optimal solution to a given AP. A little bit difficulty in the Hungarian method is to cover all the zero entries of a reduced cost matrix using minimum number of horizontal and vertical lines. However, this task has been made easy if one applies the ME Rulespresented in the Mantra technique. In this research article, we make an attempt to bring in a new technique named asCASSIfor obtaining an optimal solutionto anygiven AP using an optimality testing and improving technique. The added advantage of this method is that for any AP, the solution obtained by applying any method based on zeros assignment approach can be tested for optimality and can also be improved towards optimal, if its not optimal.