Gutman and Wagner proposed the concept of matching energy (ME) and pointed out that the chemical applications of ME go back to the 1970s. Let G be a simple graph of order n and
μ1,μ2,…,μn be the roots of its matching polynomial. The ME of G is defined to be the sum of the absolute values of
μi(i=1,2,…,n). In this article, we characterize the graphs with minimal ME among all unicyclic and bicyclic graphs with a given diameter d. © 2014 Wiley Periodicals, Inc. Complexity 21: 224–238, 2015