diff --git a/.github/workflows/build-special.yml b/.github/workflows/build-special.yml
new file mode 100644
index 000000000..e5fc87fe3
--- /dev/null
+++ b/.github/workflows/build-special.yml
@@ -0,0 +1,153 @@
+name: Special Cases CI
+
+on: [pull_request]
+
+jobs:
+  build:
+    name: ${{ matrix.name }} ${{ matrix.build_type }}
+    runs-on: ${{ matrix.os }}
+
+    env:
+      CTEST_OUTPUT_ON_FAILURE: ON
+      CTEST_PARALLEL_LEVEL: 2
+      CMAKE_BUILD_TYPE: ${{ matrix.build_type }}
+      GTSAM_BUILD_UNSTABLE: ON
+
+    strategy:
+      fail-fast: false
+
+      matrix:
+        # Github Actions requires a single row to be added to the build matrix.
+        # See https://help.github.com/en/articles/workflow-syntax-for-github-actions.
+        name: [
+            ubuntu-gcc-deprecated,
+            ubuntu-gcc-quaternions,
+            ubuntu-gcc-points-vector,
+            macos-xcode-deprecated,
+            macos-xcode-quaternions,
+            macos-xcode-points-vector,
+            ubuntu-clang-deprecated,
+            ubuntu-clang-quaternions,
+            ubuntu-clang-points-vector
+          ]
+
+        build_type: [Debug, Release]
+
+        include:
+          - name: ubuntu-gcc-deprecated
+            os: ubuntu-18.04
+            compiler: gcc
+            version: "9"
+            flag: deprecated
+
+          - name: ubuntu-gcc-quaternions
+            os: ubuntu-18.04
+            compiler: gcc
+            version: "9"
+            flag: quaternions
+
+          - name: ubuntu-gcc-points-vector
+            os: ubuntu-18.04
+            compiler: gcc
+            version: "9"
+            flag: points-vector
+
+          - name: macos-xcode-deprecated
+            os: macOS-10.15
+            compiler: xcode
+            version: "11.3.1"
+            flag: deprecated
+
+          - name: macos-xcode-quaternions
+            os: macOS-10.15
+            compiler: xcode
+            version: "11.3.1"
+            flag: quaternions
+
+          - name: macos-xcode-points-vector
+            os: macOS-10.15
+            compiler: xcode
+            version: "11.3.1"
+            flag: points-vector
+
+          - name: ubuntu-clang-deprecated
+            os: ubuntu-18.04
+            compiler: clang
+            version: "9"
+            flag: deprecated
+
+          - name: ubuntu-clang-quaternions
+            os: ubuntu-18.04
+            compiler: clang
+            version: "9"
+            flag: quaternions
+
+          - name: ubuntu-clang-points-vector
+            os: ubuntu-18.04
+            compiler: clang
+            version: "9"
+            flag: points-vector
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@master
+
+      - name: Install (Linux)
+        if: runner.os == 'Linux'
+        run: |
+          # LLVM 9 is not in Bionic's repositories so we add the official LLVM repository.
+          if [ "${{ matrix.compiler }}" = "clang" ] && [ "${{ matrix.version }}" = "9" ]; then
+            sudo add-apt-repository "deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main"
+          fi
+          sudo apt-get -y update
+
+          sudo apt install cmake build-essential pkg-config libpython-dev python-numpy
+
+          echo "::set-env name=BOOST_ROOT::$(echo $BOOST_ROOT_1_69_0)"
+          echo "::set-env name=LD_LIBRARY_PATH::$(echo $BOOST_ROOT_1_69_0/lib)"
+
+          if [ "${{ matrix.compiler }}" = "gcc" ]; then
+            sudo apt-get install -y g++-${{ matrix.version }} g++-${{ matrix.version }}-multilib
+            echo "::set-env name=CC::gcc-${{ matrix.version }}"
+            echo "::set-env name=CXX::g++-${{ matrix.version }}"
+          else
+            sudo apt-get install -y clang-${{ matrix.version }} g++-multilib
+            echo "::set-env name=CC::clang-${{ matrix.version }}"
+            echo "::set-env name=CXX::clang++-${{ matrix.version }}"
+          fi
+
+      - name: Install (macOS)
+        if: runner.os == 'macOS'
+        run: |
+          brew install cmake ninja boost
+          if [ "${{ matrix.compiler }}" = "gcc" ]; then
+            brew install gcc@${{ matrix.version }}
+            echo "::set-env name=CC::gcc-${{ matrix.version }}"
+            echo "::set-env name=CXX::g++-${{ matrix.version }}"
+          else
+            sudo xcode-select -switch /Applications/Xcode_${{ matrix.version }}.app
+            echo "::set-env name=CC::clang"
+            echo "::set-env name=CXX::clang++"
+            fi
+
+      - name: Set Allow Deprecated Flag
+        if: matrix.flag == 'deprecated'
+        env:
+          GTSAM_ALLOW_DEPRECATED_SINCE_V41: ON
+        run: echo "Allow deprecated since version 4.1"
+
+      - name: Set Use Quaternions Flag
+        if: matrix.flag == 'quaternions'
+        env:
+          GTSAM_USE_QUATERNIONS: ON
+        run: echo "Use Quaternions for rotations"
+
+      - name: Set Typedef Points to Vector Flag
+        if: matrix.flag == 'points-vector'
+        env:
+          GTSAM_TYPEDEF_POINTS_TO_VECTOR: ON
+        run: echo "Typedef Points to Vector"
+
+      - name: Build & Test
+        run: |
+          bash .github/scripts/unix.sh -t