While both the poems under our scrutiny have explored the same themes, let us understand how each poem made use of different (or similar) poetic devices and literary techniques.
The poem To His Coy Mistress involves the usage of the famous device of the 17th-century literature – Carpe Diem. This technique often took an apostrophic form and style which stressed the temporality of youth (John Larson, 1999). This technique was usually used in a poem that would further take advantage of the theme of temporary youth to entice a partner into furthering the relationship (sexually or otherwise).
From the above interface, we can very well reach the conclusion that though, both the poems do cover similar themes, that is, of love and death, the treatment given to each is entirely different. The literary techniques are used, but the purpose behind their usage is different. The themes explored are same, but the purpose behind is opposite. The poem A Valediction carries with it a tone soft, suave and ethereal, appealing the senses of the reader. However, in the poem To His Coy Mistress, the tone is romantic in the beginning, getting too crass sexuality in the end, while also horrifying the reader with certain imagery in between (imagery of death of the maiden and worms eating away). Hence, this is to conclude that like the example taken above of two poems, while the themes they share might be same, the treatment given may be different, changing the purpose of the poem and poetry and the meaning altogether.