Tom,Johns,tom.johns@email.com,14 May 2017
Imaginary,User,imaginary@email.com,23 May 2018

First,User,first.user@email.com,10 Jan 2018
Second,User,second.user@email.com,13 Feb 2018
Tom,Johns,tom.johns@email.com,16 Jun 2017
Imaginary,User,imaginary@email.com,23 May 2018

Tom,Johns,tom.johns@email.com,16 Jun 2017

import csv

with open('file1.csv', 'r') as first_csv:
    dialect = csv.excel()
    file1 = csv.reader(first_csv, dialect)

with open('file2.csv', 'r') as second_csv:
        dialect = csv.excel()
        file2 = csv.reader(second_csv, dialect)

writer = csv.writer(open('result.csv', 'w'))

output = set()

for row1 in file1:
        for row2 in file2:
                if (row1[2] == row2[2]) and (row1[3] != row1[3]):
                        writer.writerow(row2)
                        output.append(row2)

import csv

first_csv = open('file1.csv', 'r')
second_csv = open('file2.csv', 'r')
output_csv = open('result.csv', 'w')

try:
    file1 = csv.reader(first_csv, csv.excel())
    file2 = csv.reader(second_csv, csv.excel())
    writer = csv.writer(output_csv)

    output = []
    for row1 in file1:
        for row2 in file2:
            if (row1[2] == row2[2]) and (row1[3] != row2[3]):
                writer.writerow(row2)
                output.append(row2)
finally:
    first_csv.close()
    second_csv.close()
    output_csv.close()

print(output)