日本語はむずかしくておもしろいからすきです。
Japanese is difficult and interesting so I like it.

と only connects nouns, adjectives are connected either by ～で when they're na- or no-adjectives or by ～くて when they're i-adjectives, drop the final い and add くて. However, don't forget that いい and かっこいい are exceptions, they are not conjugated as いくて or かっこいくて but as よくて and かっこよくて. きらい、ちいさい and おおきい are also exceptions. きらい is a na-adjective despite ending in い, so you say 嫌いな物 and not きらいもの. ちいさい and おおきい are both, if you want to use them as na-adjectives you need to drop the final い: 小さな物, 大きな物.