Communication systems have poor performance over fading channel which can be improved by using diversity techniques. Diversity combining increases the overall received power and reduce the effect of fading. This paper presents a comparison between the conventional selection combining (SC) and maximal ratio combining (MRC) techniques for 2 dimensional signals such as MPSK and MQAM taking symbol error rate (SER) and bit error rate (BER) as comparing parameters. In both diversity combining techniques, the cases of paired and non-paired real and imaginary components are considered.  Enhanced MRC has an SNR gain over enhanced SC for the same error rate. The gain increases as the diversity order (DO) increase. Both the theoretical analysis and simulation results are shown for the comparison