diff --git a/tests/blocks/spinhalf_symmetric/test_spinhalf_symmetric_apply.cpp b/tests/blocks/spinhalf_symmetric/test_spinhalf_symmetric_apply.cpp
index e49c7101..7c7e78a3 100644
--- a/tests/blocks/spinhalf_symmetric/test_spinhalf_symmetric_apply.cpp
+++ b/tests/blocks/spinhalf_symmetric/test_spinhalf_symmetric_apply.cpp
@@ -30,6 +30,11 @@ void test_spinhalf_symmetric_apply(OpSum ops, PermutationGroup space_group,
         arma::cx_vec w2(block.size(), arma::fill::zeros);
         apply(ops, block, v, block, w2);
         REQUIRE(close(w1, w2));
+        arma::cx_mat m(block.size(), 5, arma::fill::randn);
+        arma::cx_mat n1 = H * m;
+        arma::cx_mat n2(block.size(), 5, arma::fill::zeros);
+        apply(ops, block, m, block, n2);
+        REQUIRE(close(n1, n2));
 
         // Compute eigenvalues and compare
         arma::vec evals_mat;
diff --git a/xdiag/algebra/apply.cpp b/xdiag/algebra/apply.cpp
index 894218ea..932e6890 100644
--- a/xdiag/algebra/apply.cpp
+++ b/xdiag/algebra/apply.cpp
@@ -141,6 +141,9 @@ void apply(OpSum const &ops, Spinhalf const &block_in,
 template void apply<double>(OpSum const &, Spinhalf const &,
                             arma::Mat<double> const &, Spinhalf const &,
                             arma::Mat<double> &, double);
+template void apply<complex>(OpSum const &, Spinhalf const &,
+                            arma::Mat<complex> const &, Spinhalf const &,
+                            arma::Mat<complex> &, double);
 
 template <typename coeff_t>
 void apply(OpSum const &ops, tJ const &block_in,
@@ -177,6 +180,9 @@ void apply(OpSum const &ops, tJ const &block_in,
 template void apply<double>(OpSum const &, tJ const &,
                             arma::Mat<double> const &, tJ const &,
                             arma::Mat<double> &, double);
+template void apply<complex>(OpSum const &, tJ const &,
+                            arma::Mat<complex> const &, tJ const &,
+                            arma::Mat<complex> &, double);
 
 template <typename coeff_t>
 void apply(OpSum const &ops, Electron const &block_in,
@@ -213,6 +219,9 @@ void apply(OpSum const &ops, Electron const &block_in,
 template void apply<double>(OpSum const &, Electron const &,
                             arma::Mat<double> const &, Electron const &,
                             arma::Mat<double> &, double);
+template void apply<complex>(OpSum const &, Electron const &,
+                            arma::Mat<complex> const &, Electron const &,
+                            arma::Mat<complex> &, double);
 
 #ifdef XDIAG_USE_MPI