JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div-one">I will disappear <div class="dismiss">close</div></div>
<div id="div-two">I want to disappear when #div-one disappears...</div>

CSS

.dismiss {
    display: inline-block;
    cursor: pointer;
    float: right;
    text-decoration: underline;
}
div:not(.dismiss) {
    border: 1px solid black;
    padding: 15px;
    margin: 15px;
}

JavaScript

$(".dismiss").click(function() {
    $("#div-one").hide();
});