diff --git a/optional.go b/optional.go
index 530d16e..e46dafc 100644
--- a/optional.go
+++ b/optional.go
@@ -2,7 +2,6 @@ package opt
 
 import (
 	"fmt"
-	"encoding/json"
 )
 
 // Optional represents an optional value.
@@ -170,15 +169,6 @@ func (receiver Optional[T]) GoString() string {
 	return fmt.Sprintf("opt.Something[%T](%#v)", receiver.value, receiver.value)
 }
 
-// MarshalJSON makes it so json.Marshaler is implemented.
-func (receiver Optional[string]) MarshalJSON() ([]byte, error) {
-	if !receiver.something {
-		return nil, fmt.Errorf("cannot marshal opt.Nothing[%T]()", receiver.value)
-	}
-
-	return json.Marshal(receiver.value)
-}
-
 // WhenNothing will call ‘fn’ when ‘receiver’ is holding nothing.
 //
 // It will not call ‘fn’ when ‘receier’ is hold something.
diff --git a/optional_marshaljson.go b/optional_marshaljson.go
new file mode 100644
index 0000000..6233092
--- /dev/null
+++ b/optional_marshaljson.go
@@ -0,0 +1,19 @@
+package opt
+
+import (
+	"fmt"
+	"encoding/json"
+)
+
+type jsonMarshaler interface {
+	bool | string
+}
+
+// MarshalJSON makes it so json.Marshaler is implemented.
+func (receiver Optional[jsonMarshal]) MarshalJSON() ([]byte, error) {
+	if !receiver.something {
+		return nil, fmt.Errorf("cannot marshal opt.Nothing[%T]()", receiver.value)
+	}
+
+	return json.Marshal(receiver.value)
+}
diff --git a/optional_marshaljson_bool_test.go b/optional_marshaljson_bool_test.go
new file mode 100644
index 0000000..18a88dd
--- /dev/null
+++ b/optional_marshaljson_bool_test.go
@@ -0,0 +1,46 @@
+package opt_test
+
+import (
+	"testing"
+
+	"sourcecode.social/reiver/go-opt"
+)
+
+func TestOptional_MarshalJSON_bool(t *testing.T) {
+
+	tests := []struct{
+		Value opt.Optional[bool]
+		Expected string
+	}{
+		{
+			Value: opt.Something(false),
+			Expected: "false",
+		},
+		{
+			Value: opt.Something(true),
+			Expected: "true",
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		actualBytes, err := test.Value.MarshalJSON()
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one." , testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("VALUE: %#v", test.Value)
+			continue
+		}
+
+		actual := string(actualBytes)
+		expected := test.Expected
+
+		if expected != actual {
+			t.Errorf("For test #%d, the actual value for the JSON marshaling is not what was expected.", testNumber)
+			t.Logf("EXPECTED: %q", expected)
+			t.Logf("ACTUAL:   %q", actual)
+			t.Logf("VALUE: %#v", test.Value)
+			continue
+		}
+	}
+}
diff --git a/optional_marshaljson_string_test.go b/optional_marshaljson_string_test.go
new file mode 100644
index 0000000..b33a837
--- /dev/null
+++ b/optional_marshaljson_string_test.go
@@ -0,0 +1,105 @@
+package opt_test
+
+import (
+	"testing"
+
+	"sourcecode.social/reiver/go-opt"
+)
+
+func TestOptional_MarshalJSON_string(t *testing.T) {
+
+	tests := []struct{
+		Value opt.Optional[string]
+		Expected string
+	}{
+		{
+			Value: opt.Something(""),
+			Expected: `""`,
+		},
+
+
+
+		{
+			Value: opt.Something("apple"),
+			Expected: `"apple"`,
+		},
+		{
+			Value: opt.Something("banana"),
+			Expected: `"banana"`,
+		},
+		{
+			Value: opt.Something("cherry"),
+			Expected: `"cherry"`,
+		},
+
+
+
+		{
+			Value: opt.Something("ONCE"),
+			Expected: `"ONCE"`,
+		},
+		{
+			Value: opt.Something("TWICE"),
+			Expected: `"TWICE"`,
+		},
+		{
+			Value: opt.Something("THRICE"),
+			Expected: `"THRICE"`,
+		},
+		{
+			Value: opt.Something("FOURCE"),
+			Expected: `"FOURCE"`,
+		},
+
+
+
+		{
+			Value: opt.Something("🙂"),
+			Expected: `"🙂"`,
+		},
+		{
+			Value: opt.Something("😈"),
+			Expected: `"😈"`,
+		},
+		{
+			Value: opt.Something("❤️"),
+			Expected: `"❤️"`,
+		},
+
+
+
+		{
+			Value: opt.Something("٠١٢٣۴۵۶٧٨٩"),
+			Expected: `"٠١٢٣۴۵۶٧٨٩"`,
+		},
+
+
+
+		{
+			Value: opt.Something("𐏑𐏓𐏕"),
+			Expected: `"𐏑𐏓𐏕"`,
+		},
+	}
+
+	for testNumber, test := range tests {
+
+		actualBytes, err := test.Value.MarshalJSON()
+		if nil != err {
+			t.Errorf("For test #%d, did not expect an error but actually got one." , testNumber)
+			t.Logf("ERROR: (%T) %s", err, err)
+			t.Logf("VALUE: %#v", test.Value)
+			continue
+		}
+
+		actual := string(actualBytes)
+		expected := test.Expected
+
+		if expected != actual {
+			t.Errorf("For test #%d, the actual value for the JSON marshaling is not what was expected.", testNumber)
+			t.Logf("EXPECTED: %q", expected)
+			t.Logf("ACTUAL:   %q", actual)
+			t.Logf("VALUE: %#v", test.Value)
+			continue
+		}
+	}
+}