diff --git a/flang/lib/Optimizer/CodeGen/Target.h b/flang/lib/Optimizer/CodeGen/Target.h
--- a/flang/lib/Optimizer/CodeGen/Target.h
+++ b/flang/lib/Optimizer/CodeGen/Target.h
@@ -77,6 +77,9 @@
   /// value may need to be converted to a hidden reference argument.
   virtual Marshalling complexReturnType(mlir::Type eleTy) const = 0;
 
+  /// Type presentation of a `boxchar<n>` type value in memory.
+  virtual mlir::Type boxcharMemoryType(mlir::Type eleTy) const = 0;
+
   /// Type representation of a `boxchar<n>` type argument when passed by value.
   /// An argument value may need to be passed as a (safe) reference argument.
   ///
diff --git a/flang/lib/Optimizer/CodeGen/Target.cpp b/flang/lib/Optimizer/CodeGen/Target.cpp
--- a/flang/lib/Optimizer/CodeGen/Target.cpp
+++ b/flang/lib/Optimizer/CodeGen/Target.cpp
@@ -42,6 +42,14 @@
     return mlir::TupleType::get(eleTy.getContext(), range);
   }
 
+  mlir::Type boxcharMemoryType(mlir::Type eleTy) const override {
+    auto idxTy = mlir::IntegerType::get(eleTy.getContext(), S::defaultWidth);
+    auto ptrTy = fir::ReferenceType::get(eleTy);
+    // { t*, index }
+    mlir::TypeRange range = {ptrTy, idxTy};
+    return mlir::TupleType::get(eleTy.getContext(), range);
+  }
+
   Marshalling boxcharArgumentType(mlir::Type eleTy, bool sret) const override {
     CodeGenSpecifics::Marshalling marshal;
     auto idxTy = mlir::IntegerType::get(eleTy.getContext(), S::defaultWidth);
diff --git a/flang/lib/Optimizer/CodeGen/TypeConverter.h b/flang/lib/Optimizer/CodeGen/TypeConverter.h
--- a/flang/lib/Optimizer/CodeGen/TypeConverter.h
+++ b/flang/lib/Optimizer/CodeGen/TypeConverter.h
@@ -50,6 +50,10 @@
 
     // Each conversion should return a value of type mlir::Type.
     addConversion([&](BoxType box) { return convertBoxType(box); });
+    addConversion([&](BoxCharType boxchar) {
+      LLVM_DEBUG(llvm::dbgs() << "type convert: " << boxchar << '\n');
+      return convertType(specifics->boxcharMemoryType(boxchar.getEleTy()));
+    });
     addConversion(
         [&](fir::CharacterType charTy) { return convertCharType(charTy); });
     addConversion([&](fir::LogicalType boolTy) {
diff --git a/flang/test/Fir/types-to-llvm.fir b/flang/test/Fir/types-to-llvm.fir
--- a/flang/test/Fir/types-to-llvm.fir
+++ b/flang/test/Fir/types-to-llvm.fir
@@ -203,3 +203,15 @@
 func private @foo16(%arg0: !fir.vector<2:!fir.real<16>>)
 // CHECK-LABEL: foo16
 // CHECK-SAME: vector<2xf128>
+
+// -----
+
+// Test `!fir.boxchar<n>` conversion
+
+func private @foo0(%arg0: !fir.boxchar<1>)
+// CHECK-LABEL: foo0
+// CHECK-SAME: !llvm.struct<(ptr<i8>, i64)>
+
+func private @foo1(%arg0: !fir.boxchar<2>)
+// CHECK-LABEL: foo1
+// CHECK-SAME: !llvm.struct<(ptr<i16>, i64)>