diff --git a/src/HierarchicalEOM.jl b/src/HierarchicalEOM.jl
index 1e53fe13..f3eda393 100644
--- a/src/HierarchicalEOM.jl
+++ b/src/HierarchicalEOM.jl
@@ -18,7 +18,7 @@ module HierarchicalEOM
     # sub-module Bath for HierarchicalEOM
     module Bath
         import Base: show, length, getindex, lastindex, iterate, checkbounds
-        import LinearAlgebra: I, kron, ishermitian
+        import LinearAlgebra: I, kron, ishermitian, eigvals
         import SparseArrays: sparse, SparseMatrixCSC
         import ..HeomBase: HandleMatrixType
 
@@ -26,24 +26,14 @@ module HierarchicalEOM
             AbstractBath, BosonBath, BosonBathRWA, FermionBath, Exponent, C,
             AbstractBosonBath, bosonReal, bosonImag, bosonRealImag, bosonAbsorb, bosonEmit,
             AbstractFermionBath, fermionAbsorb, fermionEmit,
-            spre, spost
-
-        include("Bath.jl")
-    end
-    @reexport using .Bath
-
-    # sub-module CorrelationFunc for HierarchicalEOM
-    module CorrelationFunc
-        import ..Bath: BosonBath, FermionBath
-        import LinearAlgebra: eigvals
-
-        export 
+            spre, spost,
             Boson_DrudeLorentz_Matsubara, Boson_DrudeLorentz_Pade, 
             Fermion_Lorentz_Matsubara, Fermion_Lorentz_Pade
 
-        include("correlation_functions/CorrelationFunc.jl")
+        include("Bath.jl")
+        include("bath_correlation_functions/bath_correlation_func.jl")
     end
-    @reexport using .CorrelationFunc
+    @reexport using .Bath
     
     # sub-module HeomAPI for HierarchicalEOM
     module HeomAPI
diff --git a/src/bath_correlation_functions/bath_correlation_func.jl b/src/bath_correlation_functions/bath_correlation_func.jl
new file mode 100644
index 00000000..b70b934c
--- /dev/null
+++ b/src/bath_correlation_functions/bath_correlation_func.jl
@@ -0,0 +1,7 @@
+include("utils.jl")
+
+# bosonic bath correlation functions
+include("boson/DrudeLorentz.jl")
+
+# fermionic bath correlation functions
+include("fermion/Lorentz.jl")
\ No newline at end of file
diff --git a/src/correlation_functions/boson/DrudeLorentz.jl b/src/bath_correlation_functions/boson/DrudeLorentz.jl
similarity index 100%
rename from src/correlation_functions/boson/DrudeLorentz.jl
rename to src/bath_correlation_functions/boson/DrudeLorentz.jl
diff --git a/src/correlation_functions/fermion/Lorentz.jl b/src/bath_correlation_functions/fermion/Lorentz.jl
similarity index 100%
rename from src/correlation_functions/fermion/Lorentz.jl
rename to src/bath_correlation_functions/fermion/Lorentz.jl
diff --git a/src/correlation_functions/corr_utils.jl b/src/bath_correlation_functions/utils.jl
similarity index 100%
rename from src/correlation_functions/corr_utils.jl
rename to src/bath_correlation_functions/utils.jl
diff --git a/src/correlation_functions/CorrelationFunc.jl b/src/correlation_functions/CorrelationFunc.jl
deleted file mode 100644
index d5a468b0..00000000
--- a/src/correlation_functions/CorrelationFunc.jl
+++ /dev/null
@@ -1,3 +0,0 @@
-include("corr_utils.jl")
-include("boson/boson_corr.jl")
-include("fermion/fermion_corr.jl")
\ No newline at end of file
diff --git a/src/correlation_functions/boson/boson_corr.jl b/src/correlation_functions/boson/boson_corr.jl
deleted file mode 100644
index e9a84a26..00000000
--- a/src/correlation_functions/boson/boson_corr.jl
+++ /dev/null
@@ -1 +0,0 @@
-include("DrudeLorentz.jl")
\ No newline at end of file
diff --git a/src/correlation_functions/fermion/fermion_corr.jl b/src/correlation_functions/fermion/fermion_corr.jl
deleted file mode 100644
index c3a37798..00000000
--- a/src/correlation_functions/fermion/fermion_corr.jl
+++ /dev/null
@@ -1 +0,0 @@
-include("Lorentz.jl")
\ No newline at end of file