Night life in Nanjing is very much alive, and you can find the epicentre in Nanjing's 1912 District, which is comparable to Shanghai's Xintiandi District. It is roughly a city block of two and three-story buildings, with paved courtyards between. Almost all are restaurants, bars or nightclubs, with a few spas and upmarket clothing shops in the mix. Many of the buildings look like they might have been around since 1912, and the newer ones match the style of the older ones. The location is great; right downtown just west of the Presidential Palace. There is underground parking for cars and extensive outdoor parking for bikes and motorcycles on the north side of the complex.
The area around Shanghai Lu, which runs between Nanjing University and Nanjing Normal University, has quite a few expats - mainly foreign students or English teachers from the two universities - and some places that cater to them. On Shanghai Lu near Guangzhou is "Blue Sky", an Aussie-owned bar with good music and a free pool table. Moving north from there is the Behind-the-Wall Cafe with reasonable Mexican food and drink. You can find good music just off Shanghai Lu, and one location for good Italian food and drink Jack's, is on the last corner before Beijing Lu.
"Ellen's" on the intersection of Shanghai Lu and Guangzhou Lu is a popular student spot. It is a western-style restaurant during the day and transitions into a bar around 8pm every night. It fills up every night with expats and foreign students, as well as plenty of young locals. Most are drawn because of the atmosphere, music, and nightly drink specials a popular one is "Free Beer Hour" between 8 and 9pm on Thursdays, in which you can drink unlimited Tsingtao free of charge. The drinks are plentiful. A whisky and Coke "bucket" is ¥25, and for many people contains enough alcohol to last the night. Make sure to get there early for a table, write your name on the wall, and say hi to Xingxing.
The Castle Bar on Zhongyang Lu close to the Gulou intersection and right next to McDonalds is Nanjing's most popular student/expat dive and is most crowded and smokey on Friday and Saturday nights. Entry is free and drinks are cheap Y15 for a bud, Y10 for a tequila and has live music on Saturday nights.
Other popular expat drinking spots include Jimmy's on Hanzhong Rd West, just past the Bank of China which is next to the YESBar nightclub/KTV and has excellent burgers, pizzas and Mexican food as well as a good choice of imported beers mostly Australian for about ¥20-30 a bottle and also has hookah pipes with various flavoured tobaccos but no illegal substances, although they also stock Rizla Superking rolling papers... they're hard to come by in China.
Finnegans Wake Irish Bar is an authentic Irish bar on the Cinnalane development just north of Sanshan Street subway station, just off Zhongshan South Road walk down the pedestrianised street next to the underground car park entrance - the bar is on the left. The bar has excellent food meals are in the ¥100 range which use ingredients sourced from Ireland and there is a good choice of drinks including Kilkenny and Guiness ¥70 a pint. Good news if your tab gets too high - they take VISA cards!
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