diff -u b/core/modules/datetime_range/datetime_range.install b/core/modules/datetime_range/datetime_range.install
--- b/core/modules/datetime_range/datetime_range.install
+++ b/core/modules/datetime_range/datetime_range.install
@@ -71,8 +71,18 @@
                   $operator = 'regular_expression';
                   $datetime_value['value'] = $datetime_value['value'] . '$';
                   break;
+                case 'empty':
+                  $operator = 'empty';
+                  break;
+                case 'not empty':
+                  $operator = 'not empty';
+                  break;
                 default:
                   $operator = 'regular_expression';
+                  // Add .* to prevent blank regexes
+                  if (empty($datetime_value['value'])) {
+                    $datetime_value['value'] = '.*';
+                  }
               }
 
               // Set value and operator.