Coplen rhymes with:
adrenaline, anglen, cahalan, catalan, eblen, edelen, enslen, evelyn, gillilan, hamblen, heinlen, insulin, javelin, lanolin, madlen, magdalen, marilyn, marilynn, masculine, maslen, medlen, michelin, micheline, monhollen, porcelain, rosellen, sabalan, schnoebelen, spracklen, stricklen, verkuilen, westphalen, zebulon
Coplen sounds like:
cableone, caplan, caplin, cephalon, chaplain, chaplan, chaplin, choplin, cipollone, civilian, cofflin, copelan, copelin, coplan, coplin, coppolino, couvillion, couvillon