Online PHP editor | output for 4kDiP

<?php $arr = [ ['Template' => 'page.html5'], ['Template' => 'page2.html5'], ['Template' => 'page.html5'], ['Template' => 'page2.html5'], ['Template' => 'page.html5'], ['Template' => 'page2.html5'], ['id' => 27, 'table' => 'tl_custom', 'type' => 'text', 'data' => [ 'fragment' => 'example', 'previewId' => 1, 'isActive' => 1, ], ] ]; $newArr = array_unique(array_map(function ($el) { return $el['Template'] ?? serialize($el); }, $arr)); // restore the last element to array $last = array_key_last($newArr); $newArr[$last] = unserialize($newArr[$last]); echo '<pre>'; print_r($newArr); echo '</pre>';