diff --git a/pkgs/applications/science/chemistry/openmolcas/MKL-MPICH.patch b/pkgs/applications/science/chemistry/openmolcas/MKL-MPICH.patch
new file mode 100644
index 00000000000..c1bc211a68e
--- /dev/null
+++ b/pkgs/applications/science/chemistry/openmolcas/MKL-MPICH.patch
@@ -0,0 +1,24 @@
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 276ae4e..5e56176 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -1304,9 +1304,9 @@ if (LINALG STREQUAL "MKL")
+       endif ()
+     else ()
+       if (ADDRMODE EQUAL 64)
+-        set (libpath "${MKLROOT}/lib/intel64")
++        set (libpath "${MKLROOT}/lib")
+       elseif (ADDRMODE EQUAL 32)
+-        set (libpath "${MKLROOT}/lib/ia32")
++        set (libpath "${MKLROOT}/lib")
+       endif ()
+     endif ()
+     set (MKL_LIBRARY_PATH ${libpath} CACHE PATH "location of MKL libraries." FORCE)
+@@ -1380,7 +1380,7 @@ if (LINALG STREQUAL "MKL")
+     find_library (LIBMKL_BLACS NAMES "mkl_blacs_intelmpi_ilp64"
+                   PATHS ${MKL_LIBRARY_PATH} NO_DEFAULT_PATH)
+   elseif (MPI_IMPLEMENTATION STREQUAL "mpich")
+-    find_library (LIBMKL_BLACS NAMES "mkl_blacs_ilp64"
++    find_library (LIBMKL_BLACS NAMES "mkl_blacs_intelmpi_ilp64"
+                   PATHS ${MKL_LIBRARY_PATH} NO_DEFAULT_PATH)
+   endif ()
diff --git a/pkgs/applications/science/chemistry/openmolcas/default.nix b/pkgs/applications/science/chemistry/openmolcas/default.nix
index 1c320335487..c5f60c395ae 100644
--- a/pkgs/applications/science/chemistry/openmolcas/default.nix
+++ b/pkgs/applications/science/chemistry/openmolcas/default.nix
@@ -1,30 +1,35 @@
 { lib, stdenv, fetchFromGitLab, cmake, gfortran, perl
-, openblas, hdf5-cpp, python3, texlive
-, armadillo, mpi, globalarrays, openssh
-, makeWrapper
+, blas-ilp64, hdf5-cpp, python3, texlive
+, armadillo, libxc, makeWrapper
+# Note that the CASPT2 module is broken with MPI
+# See https://gitlab.com/Molcas/OpenMolcas/-/issues/169
+, enableMpi ? false
+, mpi, globalarrays
 } :
 
-let
-  version = "21.10";
-  # The tag keeps moving, fix a hash instead
-  gitLabRev = "117305462bac932106e8e3a0347238b768bcb058";
+assert blas-ilp64.isILP64;
+assert lib.elem blas-ilp64.passthru.implementation [ "openblas" "mkl" ];
 
-  python = python3.withPackages (ps : with ps; [ six pyparsing ]);
+let
+  python = python3.withPackages (ps : with ps; [ six pyparsing numpy h5py ]);
 
 in stdenv.mkDerivation {
   pname = "openmolcas";
-  inherit version;
+  version = "22.02";
 
   src = fetchFromGitLab {
     owner = "Molcas";
     repo = "OpenMolcas";
-    rev = gitLabRev;
-    sha256 = "sha256-GMi2dsNBog+TmpmP6fhQcp6Z5Bh2LelV//MqLnvRP5c=";
+    # The tag keeps moving, fix a hash instead
+    rev = "f8df69cf87b241a15ebc82d72a8f9a031a385dd4"; # 2022-02-10
+    sha256 = "0p2xj8kgqdk5kb1jv5k77acbiqkbl2sh971jnz9p00cmbh556r6a";
   };
 
   patches = [
     # Required to handle openblas multiple outputs
     ./openblasPath.patch
+    # Required for MKL builds
+    ./MKL-MPICH.patch
   ];
 
   nativeBuildInputs = [
@@ -36,27 +41,35 @@ in stdenv.mkDerivation {
   ];
 
   buildInputs = [
-    openblas
+    blas-ilp64.passthru.provider
     hdf5-cpp
     python
     armadillo
+    libxc
+  ] ++ lib.optionals enableMpi [
     mpi
     globalarrays
-    openssh
   ];
 
+  passthru = lib.optionalAttrs enableMpi { inherit mpi; };
+
   cmakeFlags = [
     "-DOPENMP=ON"
-    "-DGA=ON"
-    "-DMPI=ON"
     "-DLINALG=OpenBLAS"
     "-DTOOLS=ON"
     "-DHDF5=ON"
     "-DFDE=ON"
-    "-DOPENBLASROOT=${openblas.dev}"
+    "-DEXTERNAL_LIBXC=${libxc}"
+  ] ++ lib.optionals (blas-ilp64.passthru.implementation == "openblas") [
+    "-DOPENBLASROOT=${blas-ilp64.passthru.provider.dev}" "-DLINALG=OpenBLAS"
+  ] ++ lib.optionals (blas-ilp64.passthru.implementation == "mkl") [
+    "-DMKLROOT=${blas-ilp64.passthru.provider}" "-DLINALG=MKL"
+  ] ++ lib.optionals enableMpi [
+    "-DGA=ON"
+    "-DMPI=ON"
   ];
 
-  preConfigure = ''
+  preConfigure = lib.optionalString enableMpi ''
     export GAROOT=${globalarrays};
   '';
 
@@ -68,6 +81,8 @@ in stdenv.mkDerivation {
 
   postInstall = ''
     mv $out/pymolcas $out/bin
+    find $out/Tools -type f -exec mv \{} $out/bin \;
+    rm -r $out/Tools
   '';
 
   postFixup = ''
@@ -84,6 +99,7 @@ in stdenv.mkDerivation {
     maintainers = [ maintainers.markuskowa ];
     license = licenses.lgpl21Only;
     platforms = [ "x86_64-linux" ];
+    mainProgram = "pymolcas";
   };
 }