This article investigates the bipartite output formation tracking problem of heterogeneous singular multiagent systems (MASs) over a signed digraph on which two types of cases without and with input saturation are considered, respectively. First, a novel formation tracking protocol is presented for heterogeneous singular MASs in the absence of input saturation constraints. In the proposed protocol, a distributed observer with adaptive updating mechanism is constructed for each follower, which does not involve global information of communication graph. Based on the observer, the designed controller addresses bipartite output formation tracking of heterogeneous singular MASs in a fully distributed fashion. Then, by the output regulation theory and low‐gain feedback technique, a low‐gain formation tracking protocol is proposed to achieve semi‐global bipartite output formation tracking for heterogeneous singular MASs subject to input saturation constraints. Finally, two simulation examples are given to illustrate the feasibility of theoretical results.