diff --git a/lib/src/event_controller.dart b/lib/src/event_controller.dart
index eeb97a03..4a395a51 100644
--- a/lib/src/event_controller.dart
+++ b/lib/src/event_controller.dart
@@ -159,7 +159,9 @@ class EventController<T extends Object?> extends ChangeNotifier {
         'The end date must be greater or equal to the start date');
     if (_calendarData.eventList.contains(event)) return;
     if (event.endDate.difference(event.date).inDays > 0) {
-      if (event.startTime!.isDayStart && event.endTime!.isDayStart) {
+      if (event.startTime == null ||
+          event.endTime == null ||
+          (event.startTime!.isDayStart && event.endTime!.isDayStart)) {
         _calendarData.fullDayEventList.addEventInSortedManner(event);
       } else {
         _calendarData.rangingEventList.addEventInSortedManner(event);
diff --git a/lib/src/extensions.dart b/lib/src/extensions.dart
index c852bbbe..a246119f 100644
--- a/lib/src/extensions.dart
+++ b/lib/src/extensions.dart
@@ -170,17 +170,20 @@ extension MyList on List<CalendarEventData> {
   // the existing list of CalendarEventData.
   void addEventInSortedManner(CalendarEventData event) {
     var addIndex = -1;
+
     for (var i = 0; i < this.length; i++) {
-      if (event.startTime!.compareTo(this[i].startTime!) <= 0) {
+      if ((event.startTime?.getTotalMinutes ?? 0) -
+              (this[i].startTime?.getTotalMinutes ?? 0) <=
+          0) {
         addIndex = i;
         break;
       }
     }
 
     if (addIndex > -1) {
-      this.insert(addIndex, event);
+      insert(addIndex, event);
     } else {
-      this.add(event);
+      add(event);
     }
   }
 }