The light/dark imagery that is used in Act II Scene 2 of Romeo and Juliet establishes the pattern of Romeo and Juliet's meetings; namely, in the dark. For, throughout the play, the lovers are only safe in the night time. It is in the daylight that Romeo must flee Juliet's room after they consummate their marriage, and it is in the daylight that Romeo causes Mercutio's death and, in turn, slay Tybalt in anger.
In addition, the beautiful imagery of light and darkness beautifies the verses of Act II and provides the figurative language of courtly love which Romeo and Juliet employ whenever they talk to each other. Courtly love is an experience between erotic desire and spiritual attainment. Thus, Romeo's refers to Juliet's being "a winged messenger of heaven" while he later asks her "Wilt thou leave me so unsatisfied?" Of course, in Act I, Scene 5, the sonnet that Romeo and Juliet share in which they speak of pilgrims on a spiritual journey and kissing illustrates courtly love, as well.
1. Juliet cannot see Romeo, so she feels free to profess her feelings out loud, unaware that he can hear her.
2. Romeo and Juliet couldn't be together in the first place if they could be seen; darkness gives them the cover they need to have a conversation.