Alessandro Carbone

How many times have you wished to minify in a clean way all the stylesheets and scripts of a WordPress website?
AssetsMinify takes every CSS and JS asset included using <code>wp_enqueue_style()</code> and <code>wp_enqueue_script()</code>, merges and minifies them.
You can also use AssetsMinify to create your WP theme using Compass / Sass / Less without configuring any <code>config.rb</code> or that kind of stuff.
AssetsMinify is based on Assetic library.
<a href="https://github.com/acarbone/AssetsMinify" rel="nofollow ugc">Fork me on Github</a>.

AssetsMinify

Use Compass, Sass, Less, Stylus, CoffeeScript (and more ...) to develop your themes and minify your stylesheets and JavaScript.

Nirmal Kumar Ram

Magnigenie

LessCSS
LESS extends CSS with dynamic behaviour such as variables, mixins, operations and functions.Implements LessCSS in order to provide lots of interesting features for the theme development.
How to use ?
Just enqueue the LESS files (with .less extension) as it is usually done for the CSS ones, and the corresponding CSS files will automatically be generated and added to the site.
Important Notes
1.This plugin is based on <a href="http://leafo.net/lessphp/" rel="nofollow ugc">lessphp</a> by Leaf Corcoran
2.This plugin generates the css file under “/wp-content/uploads/lessify-cache” and therefore you need to define your images and any external links on you less file using the themeurl variable available with this plugin and if you use relative url then it will not work as we are saving the css file in a different location.
3.In order to use themeurl variable with the images you can do something like this
body{ background-image: url(@{themeurl}/images/bg.png); } 
the plugin also comes with
another variable <code>lessurl</code> which provides the url where the less file is present.

Lessify WordPress

Combine the power of WordPress with the power of Less and create something awesome.

AssetsMinify vs Lessify WordPress