Usually I use $(\"#id\").val() to return the value of the selected option, but this time it doesn\'t work.
The selected tag has the id aioConceptName
I hope this also helps to understand better and helps try this below,
$('select[id="aioConceptName[]"] option:selected').each(function(key,value){
options2[$(this).val()] = $(this).text();
console.log(JSON.stringify(options2));
});
to more details please http://www.drtuts.com/get-value-multi-select-dropdown-without-value-attribute-using-jquery/